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Dual SIM Android phones: Dual standby vs dual active

Everything you need to know on choosing and using dual SIM Android phones.

Dual SIM Android phones: Dual standby vs dual activeThere are many wrong or misleading blog posts and reviews on dual SIM Android phones!!

So, I prepared this guide to help you understand what’s the difference between dual standby and dual active phones and how to choose dual SIM android phones to meet your needs.

Table of Contents hide
1) What are dual SIM Android phones? Who need them?
2) Dual standby vs dual active: what’s the difference?
3) Why and when some dual SIM dual standby phones may work like dual SIM dual active phones?
4) Why it is hard to get dual SIM dual active Android phones?
5) Is my dual SIM Android phone dual standby or dual active?
6) What is 4G+2G and dual 4G
7) List of dual SIM dual active Android phones

What are dual SIM Android phones? Who need them?

Most mobile phones (including the dumb phones) require a SIM (subscriber identification module) card to connect to carrier’s mobile network.

All mobile networks based on GSM technology (which has about 90% market share) require an SIM card to identify the user.

CDMA-based mobile networks, technically, do not require the SIM card because user can be identified through devices. But as almost all carriers is moving to 4G LTE (Long Term Evolution), which requires a SIM card, almost all carriers now require SIM card based phones.

By default, a mobile phone uses one SIM card. This is sufficient for most users.

But for some users who need a business number and a separate personal number, they may want to use 2 or more SIM cards in one phone, instead of carrying two or more phones.

So, for long time, mobile phone manufacturers have developed multi SIM (dual SIM, triple SIM or even quad SIM) phones for these users.

Nowadays, in addition to business users,  more users may want to use one SIM card for mobile data and the other one for voice. Many travelers may also want to take advantage of a local SIM card together with a home SIM card.

Anyway, dual SIM phones are NOT new things. Such phones were offered even before Android.

Dual standby vs dual active: what’s the difference?

But not all dual SIM Android phones were created equal.

There are mainly two types of dual SIM Android phones: dual standby and dual active.

The difference is NOT small.

Dual standby means both SIM cards can connect (listen) to their own mobile networks. These two SIM cards in the same phone can even be from one carrier. In this case, both are connected to the same mobile network independently, just like from two different phones.

However, in dual standby Android phones, there is only one set of hardware (mainly receiver)  to serve two SIM cards. In other words, two SIM cards share one set of hardware through time sharing algorithms implemented in the software level.

For dual active Android phones, there are usually two sets of receivers. Each SIM card uses its own receiver.

The difference between dual standby and dual active phones is significant when one of the SIM card is engaged in a call or data connection through 2G network.

Because 2G voice calls uses circuit switched data connection. This means once the call is engaged, the SIM card will use the receiver exclusively. So, for dual standby phones, this means the other SIM card will lose mobile network connection (unregistered). If someone calls you to the number associated with the unregistered SIM card at this time, the call will be unreachable. Depending on your settings with your carrier (not your phone), you can choose to divert call to voicemail, or divert call to other numbers, or do not divert.

For dual active phones, this is not an issue because each SIM card uses its own receiver. When one SIM card is engaged in call, the other SIM card is still registered in its own carrier’s network and is reachable. In this case, if someone calls this number, depending on vendor’s software implementation, you usually will get a notification for an incoming call. You can choose to hold the call or even initiate a 3-party voice call (conference call).

So, the difference between dual standby and dual active dual SIM Android phones are:

  • No difference when the phone is in standby mode.
  • When you are using one of the SIM cards for voice calling (or sending SMS) through 2G network, the other SIM card will be disabled in dual standby phones.

In this sense, dual standby usually is referred as dual standby only, or dual-standby-single-active.

When using 3G or 4G mobile data on one SIM card on a dual standby phone, the other SIM card will NOT be disabled. 3G and 4G LTE mobile data connection always uses packet switching, which does not require exclusive usage of the receiver. Although 2G (or 2.5G as named by some carriers) mobile data GPRS (General Packet Radio Service) and Edge (Enhanced Data Rates for GSM Evolution) actually are both packet based. But due to the implementation, exclusive use of the receiver is usually needed.

If you want to make both SIM cards always available in a dual standby phone, you need to set up call forwarding and enable call waiting as explained in How to make two SIM cards always available in dual SIM dual standby Android phones page.

Why and when some dual SIM dual standby phones may work like dual SIM dual active phones?

In recent years, many carriers have rolled out voLTE (voice over LTE). Some may marketed it as HD voice or crystal voice or something else. VoLTE uses 4G LTE mobile network for voice calls. This means the call, if implemented properly, does not require exclusive use of the receiver. It is similar to VoIP (voice over IP); but with different protocols. .

So, dual standby Android phones may work like dual active phones when you are engaged a voice call through voLTE.  In this case, if someone calls you in the other SIM card, you should get an incoming call notification as in a dual active Android phone.  But you cannot put any call on-hold or on-wait, even your carrier support these.

In dual active Android phones, normally you can put any call on-hold or on-wait. You can even initiate 3-party conference call if your carrier mobile network support it.

Anyway, you can follow this guide to make both SIM cards available at all times even when you are engaged in a call in one SIM card.

Why it is hard to get dual SIM  dual active Android phones?

Dual SIM Android phones can be a good choice for many consumers. But a lot of Android flagship phones in most regions support only single SIM card. Dual SIM phones usually are linked  to “cheap” phones.

Moreover, it is obvious dual active is superior to dual standby.  But you will find it is very, very difficult to find a high-end dual active dual SIM Android phones in the market. Most of dual SIM Android phones are dual standby only.

Dual standby phones only require additional space for SIM card. So, the cost increase compared to single SIM version is marginal.

Dual active Android phones require additional hardware. But the additional hardware cost should be just a few bucks.  Modifications of software are also required.  This deters many small Android vendors. Sometimes, additional patent royalty may be required.

In addition, the standby time of dual active phones will be reduced significantly (almost halved) given the same battery capacity. This sounds matters. But actually, it does MOT matter for most users. For example, Google Pixel XL phone has a standby time of 23 days.  Most users charge phones every day. So reducing the standby time to 12 days is not a big deal.

The real reason is that almost all carriers do not like (or even hate) dual SIM phones, or multiple SIM phones. In a lot of regions, most consumers are under 12-month or 24-month “contract”. And phone companies offer some forms of subsidies for phones.  For users who need two SIM cards, they are happier to sell them two phones and lock the user into two contracts.  If they offer high quality dual SIM phones, the customer may only sign one contract and buy a cheaper prepaid SIM card (maybe from other provider to get better coverage).

So, it is not strange that carriers relying on “contracted” customers resist dual or multiple SIM card phones. If the markets are dominated by such carriers, for example in US, most phones have only one SIM card slot. While the same phone in other market may support two SIM cards. For example, Galaxy S7 and Galaxy S7 edge have a SIM card+ SIMcard/micro SD card combo slot. In US market, it becomes a SIM+micro SD only.

Big phone manufacturers are also reluctant to build dual SIM phones. They also want to sell more phones. Samsung only started to make flagship phones dual SIM capable in 2016. Before 2016, they usually released a duo version in very limited markets. As mentioned, dual standby phones does not increase cost for manufactures.

For dual active Android phones, big players don’t want to build them. The additional cost of a few dollars on each phone will erode a few million dollars profit if the phone just sell 1 million units. FYI, new Galaxy S devices (since Galaxy S3) usually could easily sell 50-80 million units in that year when it was released. In addition, additional software maintenance may be needed.  For small Android phone manufactures, it is hard for them to swallow the cost without increasing the price.

Therefore, the reality is that it is hard to get decent dual active Android phones. But more and more phones will support two SIM cards (albeit dual standby only).

Is my dual SIM Android phone dual standby or dual active?

Most dual SIM Android phones announced after 2014 are dual standby only. This is due to the upstream component supply is more or less standardized in 2015.

The simple way to test whether the dual SIM Android phone is dual standby or dual active is to call each other in the phone.

Of course, you should check with the vendor on the official information.

What is 4G+2G and dual 4G

There are mainly two types of dual SIM phones in the market: 4G+2G, or dual 4G.

4G+2G dual SIM phones can connect only one SIM card to 4G (or 3G) network. The other SIM card can only connect to 2G.  Usually, the SIM card slot does NOT matter. Most dual SIM Android phones allow you to specify and change them. For example, you can specify which SIM card is used for data in Moto devices (Moto G, Moto E, Moto X and Moto Z)

Dual 4G means both SIM card can connect to 4G (or 3G or 2G) network in standby mode.  This matters in some regions where 2G network has been or will be phased out. For most dual SIM dual standby 4G phones, when one SIM card connect to 4G (usually the card you assigned for mobile data), the other card will connect to 3G voice (UMTS).

If your carrier does not support 2G, your 4G+2G dual SIM phone  then can only use one SIM card.

Some phone vendors may update the firmware to convert 4G+2G dual SIM Android phones to 4G+3G dual SIM Android phones. For example, Galaxy S7 and Galaxy S7 edge in some (not all) regions, after the firmware udpate,  now can work in this way (the official specs are still 4G +2G only).  But please note, most vendors will not update it.  Don’t count on vendors.

So, you should know whether you need to get dual 4G phones.

List of dual SIM  dual active Android phones

It is hard to get a dual active Android phones.

Here is a non-exhaustive list of dual active Android phones;

  • ASUS ZenFone 2 (ZE551ML)
  • ASUS Zenfone 2 Laser ZE551KL
  • Huawei Ascend Mate 7
  • Samsung Galaxy Ace Duos S6802
  • HTC Desire 700
  • HTC Desire 501 dual sim
  • Sony Xperia C4 Dual (not confirmed)
  • Sony Xperia M4 Aqua Dual (not confirmed)
  • Lenovo Vibe X2
  • Sony Xperia SP dual

In 2016, there were NO dual active Android phones released by major Android vendors (Samsung, LG, Motorola/Lenovo, Huaiwei, ASUS, Acer, Sony, HTC, Xiaomi, Oppo and ZTE).

In 2017, up to now, there have been NO dual active Android phones released by major Android vendors.

Do you have any questions or comments on dual SIM Android phones?

If you have any questions on choosing or using dual SIM Android phones, or if you want to share your thoughts or experiences on dual SIM Android phones (dual active or dual standby),  please let us know in the comment box below.

For questions on Android Nougat (Android 7.0 and 7.1), please check Android Nougat guides page.

For questions on Android Marshmallow (Android 6.0), please check Android Marshmallow guide page.

For question on Android Lollipop (Android 5.0 and 5.1), please check Android Lollipop guide page.

For other Android questions or problems, please check Android 101 page.

Reader Interactions

Comments

  1. Richard Felton says

    Hi 🙂 Can you please tell us which phones are dual sim dual active dual 4g (or at minimum dual 4g+3g or 3g+3g… since 2g is going away in the US that would kill the dual function. Excellent article by the way.

    Reply

  6. Mobz says

    Hi, Thanks for the informative article. Can you please inform whether Huawei Mate 8 & Mate 9 are dual SIM active?

    Thanks

    Reply

  7. Elena says

    Awhile ago I read somewhere that if you use a Dual Sim phone with two phone lines ( whether they are active or standby) you cannot use an SD card for extra storage because the second slot is used for the phone. Is this true?

    Reply

  8. W.Howyarth says

    Does it mean if i buy a dual sim standby phone once i stop talking or texting on one carrier the other carrier can ring or text me?
    Thankyou W.H.

    Reply

  9. Mario says

    I have Honor 8 and it is probably one of the last one which has a full dual sim active functionality. The newest phones Huawei Mate 9 and P10 haven’t got it. Now Huawei offers Honor 8 Pro (V9) and I wonder if it has dual active.

    Reply

  10. Peter says

    Simon, Thank you, This is the best article on dual sim I have seen. One aspect is the dual sim active phones look like they may not be upgradeable to Nougat OS. How big a deal is this?

    Reply

  12. Andy says

    Hi, I am using Doogee T5 and have 2 SIM cards on this phone. However at any one time, I can only have one SIM in 3G mode and the other SIM will be on 2G mode. Is this considered as dual standby? Is there any ROM that can allow both SIM to be set as 3G? The reason to have both in 3G is because there will be no more 2G support and I would like to use SIM 1 for data and SIM 2 for phone/sms.

    If there is no ROM or settings to enable 3G for both SIMs, please advise which brand and model of phone have such feature.

    Thank you.

    Reply

  14. Steph says

    Hi, thanks for all the good information ! I am still looking for answers for my new phone purchase. I currently own a dual-standby phone and it does not work properly for my type of use.

    Here is what I am looking for, some features are “nice to have” …

    Dual-Active phone
    Minimum Android 6.0 (7.x would be great)
    Fingerprint reader
    4.8 to 5.4in screen
    Good battery for a good day of work usage

    “nice to have” features :
    NFC

    Reply

  15. Ron Abernethy says

    Hi Simon
    Thanks for an excellent article, I have a Samsung Note 5 dual sim, which I like but unfortunately all the 2g networks will be turned off in Australia. Do you know is there any firmware updates that I can use on the Note 5 to allow me to use my Note 5 on a 4g/3g dual system. Or is there ways of making my Note 5 a 4g
    Dual Standby phone.

    Thanks
    Ron

    Reply

  16. Dani says

    Wonderfull! Thank you!

    And I got a question. My goal is to enlarge the throughput of the network. At some areas, the actual speed of the supplied internet is not high. Same with stability.

    I’d like to imporve this, by having , actually, two internet streams, combined into one – faster and more reliable.

    Or better, with the quad sim phones , to actually combine 4 internet stream into one with a higher throuput.

    Am I on track? Using this technology?

    Reply

  17. ZP says

    Hi,

    I’m currently looking for a dual sim 4G phones which can serve the following purpose:

    I need Whatsapp to work on both numbers, but calls and SMS will mostly be active on one number only.

    For this, will I be needing dual active phone, or dual standby will suffice?

    Will Samsung S8 serve this purpose?

    Reply

  18. C Sledge says

    Great article and timing now that I have a need for dual SIM. I got an unlocked LG G5 dual SIM for use in US on AT&T. I was able to get each SIM to work if it was enabled for mobile data (only one at a time). However, if SIM1 was enabled for mobile data, I wasn’t able to receive calls/text on SIM2. I thought that SIM1 would be on 4G and SIM2 would be on 3G (AT&T disabled 2G earlier thus year) but apparently that’s not the case?

    I’m assuming the G5 is a dual standby phone?

    Reply

  19. Alli says

    I want to start by saying this was an excellent article and it answered many of my questions regarding dual sim phones. Now to my personal inquiry: I currently have 2 phones one for work and one personal. The contract for my personal phone is about to be up so I’m looking to get a new phone and possibly even switch carriers. I’m tired of carrying around 2 phone and have been looking into getting a dual sim phone. My work phone has an unlimited data plan so I was thinking about using that sim for all my data needs and then having a personal plan that just covers talk and text. I’m worried about missing calls. What exactly is the risk of missing calls with a dual sim standby phone. I would normal just get the active because it’s obviously the better choice between active and standby but the phone options are much more limited (and dated). The Asus Zenfone 2 Laser ZE551KL appears to be the best available option for a dual sim active phone. However, I’m wondering how much I need it to be active rather than getting one of the newer phones which offer dual sim standby. I also don’t like the idea of a hybrid slot where I lose the ability to have a microSD card so any phones that don’t have a designated slot for dual sim and microSD are out. Does anyone have any suggestions for phones that may satisfy my needs? Or any information that may help me make a decision would also be appreciated? TIA

    Reply

  20. chan says

    hello everyone. i just got my new samsung c9 pro and it has dual sim active on this phone, meaning it can received call on both sim cards. hopefully this will be the answer for ally.
    thanks

    Reply

  21. Dave says

    Great article. Do you have any updates re 4g dual active? I’m not sure if the
    ASUS ZENFONE 3 DELUXE (ZS570KL DUAL SIM 4GB RAM 32GB 4G LTE) is dual active 3g/4g

    Reply

  22. moe says

    Can you please explain how a 4g+3g dual sim standby phone can work as dual active. It’s very crucial for me that I don’t miss calls. I recently bought the lg v20 dual sim h990N. The phone has an issue of its own. When I place a call on sim one it drops from 4G to 3G during a call and my data becomes limited, why does that happen?

    Reply

  25. Ali JAwad Khalid says

    Hi Simon,

    Its indeed great to read your comments and support. I am looking forward to buy a dual sim dual active mobile these days. Can you please suggest a list of most recent cell phones which support dual sim dual active feature. Best regards.

    Reply

  26. Hourii says

    Hi thank you for a very informative article. I have just changed from samsung A8 as i beleive it has the 4g+2g combo. Spore has phased out 2g n hence dual sim ceased to work. So i just got a new phone samsung s7 edge. Though voice calls works now…but Data Roam doesnt work for my second sim when using in Spore. Fyi my 1st sim is by spore carrier and 2nd SIM is by Malaysia carrier. I go back and forth daily between the 2 countries. No issue with using both sims for data roam/mobile data when in Malaysia
    Pls help

    Reply

  27. john says

    Great article, thank you for that.
    I have Honor 7 and Honor 8 (official European Version) and these seem to be dual active, as they can handle two calls at the same time in different networks. Honor is marketing the devices with double or triple antenna technology, so maybe the one modem (as you say they have one modem only) can handle two connections at the same time? Nevertheless, the second sim is always 2G only.
    So you might watch the Honor 8 Pro and today there will be the release for the Honor 9 (Chineese Version)…

    Reply

  28. Bjoern says

    Hi Simon,
    Thank you for all the very great information – I am amazed and thankful.
    I am looking to replace my “old” Bauhn Sphere phone which was sold to me as “DUAL 3G SIM” – but after the 2G network from Telstra was closed only 1 Sim kept working – the other “slot” always defaulted to 2G. (so much for misleading sales). Now I am looking for a “DUAL 3G or 4G standby phone with ADDITIONAL slot for an SD card. I was sold the Oppo 9s Plus as such a phone in Melbourne, but as I could not work out how to insert both SIM as well as the SD card I went to their other shop in Bendigo and they confirmed that that phone did not have the capacity of having all 3 cards installed – either 2 SIM or 1 SIM plus 1 SD card – so they returned my money.
    I was told the LG V20 has this function – but I don’t like the shape, size and whole feeling of that phone.
    Do you know of any other good and reliable phones that offer all this or am I asking for too much?
    Thank you in advance for any assistance in that matter.

    Reply

  29. Bruno Cardillo says

    Hi Simon,

    Thanks again for your well researched article and great questions from your readers.

    I thought I would just plainly ask a few questions that i think that may answer what many are thinking:

    1. Is there, at the moment, any models with a dual sim Dual Active 4G with separate SD Slot?
    2. Is there, at the moment, any models with a dual sim Dual Active 4G without separate SD Slot?
    3. Is there, at the moment, any models with a dual sim Standby 4G with separate SD Slot?
    4. Is there, at the moment, any models with a dual sim Standby 4G without separate SD Slot?

    Thanks Simon.

    Reply

  30. R3 says

    Thanks for an amazing article. Ive a note5 duos which only supoorts a dual sim standby mode. Whilst most are concerned about not missing calls on both sims, what is most impt for me is to keep my data connection in sim2 active while engaged in a call in sim1. Is there a setting modification that I can do to allow this capability? Thanks in advance!

    Reply

  31. Sree says

    Hello simon superb information.
    Presrntly am using asus zen 551 n its dual active in india. However fedup with tge phobe as it gives frequent headaches like phone hungs, voice not clear, last two days microphone not working and need to send for servicing fortunately under warranty n just 6 montgs old.
    Can you pl.suggest me any otger dual sim active phones w/o any manual call forward setting in androud.

    Reply

  32. Viola says

    Thanks for this very helpful article.

    If I purchase a dual standby high end phone will the second SIM be affected during texting or sending emails or is it just during voice use that calls to the second SIM become a problem?

    If I go for a dual active phone what’s my best bet for a reasonable smart phone 4G+3G for UK use ?Thanks

    Reply

  33. Wolverine says

    Hey Simon, i love the detailed research on this page so thanx for that. I seriously hate not finding a dsda phone more easily. I was wondering if you could explain the difference between the Zenfone 2 deluxe special edition and LG v20 and list some significant factors to consider in both phones? Also this Zenfone 2 deluxe special edition isn’t easy to find. Any idea where I can buy and brand new one? (I would appreciate any update emails on dsda phones especially with 4g + 4g call capabilities. Thank you for all your time and effort. Severely good article you wrote on dsda phones

    Reply

  34. Christoforos says

    Hello and thanks a lot about the fruitful information. I am going to university this year and since my contract with the provider has ended last month I was thinking of placing a new device in the contract and paying it for it monthly. Also, since I am from Cyprus which is in Europe and Home Roaming Services in Europe have been cancelled in May I was thinking of buying an Active Dual SIM phone in order to have a Cypriot and a British Card ( Country of Studying) and spend less when communicating back to Cyprus with the Cypriot card and likewise when communicating to Britain with the British Card. Do you know if OnePlus has designed any Active Dual Sim model? And Moreover, if am using a 4G service from one card and someone calls me in the other my phone would appear to them as switched off?

    Thanks in advance.

    Reply

  35. Amos Oz says

    Are there any dual sim 4G phones with automatic failover from one 4G network to another if one of the 4G sims has a poor connection? Or is there any dual sim smartphone which can support dual 4G data at the same time from the 2 different 4G sims, allowing the phone to combine data usage across two networks together resulting in a more stable or faster connection.

    Reply

  36. Terry LG Constant says

    Hey Simon, loved this article! I read it with great attention as I recently bought an LG V20 after having a really disappointing experience with the Samsung A5 2017. I had an LG G2 before these phones and am really happy to go back to LG for a number of reasons, mainly the fingerprint scanner location, dual camera, exapandable storage, removable back/to carry spare batteries and the overall spec.

    The dual sim capability was kind of a second thought for me as I didnt see much use having not had one in the past. I do remember having a case back in the day with an old Nokia that allowed a physical switch on the back to move over to the second sim. Sounds like possibly quite similar to a standby second sim? Although from reading your article now, I can have two PAYG sims in the UK/Europe and can take calls on either simultaneously, but if im on a call on one sim, and do not have forwarding activated, the second number is unreachable.

    As my LG V20 is a DUAL standby sim phone (I have the B&O version which is great for its Quad DAC!), there is a quick touch menu button that simply says switch sim, so I can move seamlessly between the two sims. I guess this doesnt change anything about my interface, the look etc, accounts I access, emails etc, but will allow me to access different contacts on different sims?

    Second question, sorry if its dumb, but presumably these different sims can connect to different carriers?

    Thanks and im intrigued by the V30….I wonder how much awesome this phone could get, the wide angle camera is insane! I guess the straightforward spec update? It is a trade off between removable back vs waterproof/IP67 eh.

    Reply

  37. Arshad Saeed says

    Simon,
    Thank you very much for the superb article loaded with loads of useful info in very simple words.
    I am also interested in buying an active dual sim phone but looks like my best bet would be to settle for a dual standby phone as I want real high specs like more than 5.7″ QHD screen (bigger the better), 4Gb ram, 64Gb storage, separate SD card slot, Preferably hi-res dual camera, fast + wireless charging, metal body, newest possible Android etc. Do you think if I wait until end September, 2017, such a phone would be available or there is any such model already available? I will using the phone in USA and Pakistan mainly and can purchase in any country, preferably USA. Pl advise. Thanks.

    Reply

  38. Ian M says

    Excellent article.
    I have a LG G3 dual sim with sim 2 card for gsm only.
    The google contacts can be linked to either of the sim cards. This allows me to use the work sim for work contacts.
    Do you know if this function can be transferred to other dual sim phones or do I have to wait for a new LG dual sim phone with 3G at least on sim 2?
    Does such a phone exist?

    Reply

  39. Tasos says

    Simon,
    that was (actually still is) an amazing article! Thank you for all this information and the kindness to answer every single question. I have been researching for dual active – dual 4G technology for days and my conclusion is that only Asus ZenFone (some of them) are suitable for real dual active 4G.

    I was searching for more information about Zenfone Go and Zenfone GoTV (unfortunately both have model code ZB551KL). But it seems to be only dual stand by (but both slots are for 4G cards).

    Looking in the AsusZenFone 2 series i noticed that not all ZenFone2 are dual active. For example I found Zenfone2 with model name ZE551ML. In its specs it says clearly that it has two modems (Intel 7262 + Intel 2230) but only sim 1 supports 4G.

    If someone needs a smartphone to put a sim with unlimited data and another sim for call and text, then this would be the most suitable choice in the market.

    It is difficult to find something more about Huawei Mate Series (there are no dual models in Greece) and about Huawei Honor 6 or 7. I can’t find any specs. If someone knows, I would appreciate any info.

    Reply

  40. Lee says

    Hi Simon,

    Thank you for the wonderful detail in your article. it is much appreciated.

    I have an old Samsung gt-s7562. I believe that it is dual sim active, not passive, and I have recieved calls on one line, whilst talking on the other. I have had problems though with ‘call divert when busy’ settings, which seem to change themselves or grey themselves out, so they cannot be changed. Am I mistaken, is this phone actually ‘active’ as i have always thought ?

    Kind regards, Lee

    Reply

  41. John says

    Hi Simon,

    Thanks for the excellent article. My Zenfone 2 recently packed in so I was in the market for a new active dual sim phone. I saw mixed reports that the Huawei Mate 8 had active dual sim. I found an incredible deal for the Chinese model (NXT-AL10) and decided to take the risk.

    I can confirm that the phone is in fact active dual sim as I can receive calls from both cards at the same time. Not sure if this functionality is limited to just the Chinese model or not. But the only difference on paper between this and the international variant is the RAM and storage options.

    Reply

  42. Dee says

    Hi Simon

    Thank you very much for sharing your extensive knowledge here.

    My situation is that I redirect internet landline number to European mobile number and I text back from the European mobile number. I use iPhone as I am used to it. I tried years ago a Samsung Note II but couldn’t get used to it.

    I am very often is South East Asia and I user a mobile WiFi device with local data card. iPhone is permanently connected through WiFi to it. My issue is that it takes ages to connect European calls and I often miss calls as customers hung up as it’s not ringing for a long time.

    On my display I see a local number and not the original caller’s number. Therefore, U can even not call back.

    For this reason I am considering to change to a dual sim phone.

    I would redirect European internet landline directly to local SEA mobile number, European mobile number redirect permanently to European internet number as long as I am in SEA, I assume this would be the cheapest option. The European mobile number would not receive any calls but receive and send text messages and I would also use WhatsApp from that number using WiFi (mobile data roaming switched off).

    I would need the same contacts for both SIM.

    I hope, I can reduce the connecting time dramatically like that.

    In your opinion, does that make sense and if yes, which handset to you recommend. If not, do you have a better solution?

    Reply

  43. Zoran says

    Hi Simon, correct me if I am wrong but oneplus 5 should be dual active Android phone, at least phone specifications are claiming that, am I I right?

    Reply

  44. Mack says

    Hello Simon
    Great article, good job.
    Where is 2G network not available anymore? I live in UK and would like to use main sim card from English carrier and second sim card from other EU country. Of course would like to have dual sim active at all time. Is the new BlackBerry KEYone Limited Edition Black from India will do the job properly? Is there is Volte available at the O2 network in UK?
    Thanks

    Mack

    Reply

  45. Gentle says

    Hello Simon
    Thanks for your excellent job. Phone cameras are very important for me. I’m living in Europe and use to travel to middle east. I’m in need of a dual sim phone to use internet in middle east. I found that the best camera is in iphone X and second is Galaxy note 8. I like IOS because it’s more secure and stable OS but don’t like Apples conservative behavior. Should I choose iphone X + BT dual sim adapter or Galaxy Note 8 dual sim? Which BT dual sim are more stable and reliable ?
    ps. I have Xiaomi Mi Max and it’s very nice dual sim phone except the camera.
    Thank you.

    Reply

  46. Tetsu says

    Hi Simon, thank you for writing up a great article that clears up the “dual active” terminology!

    In one of the above previous replies, you said that there are no dual active phones would support dual active 4G+3G in the current market.

    However, if you look at the specs for Asus Zenfone 2 Laser ZE551KL (dual active phone) – https://www.asus.com/us/Phone/ZenFone-2-Laser-ZE551KL/specifications/
    it shows that:
    SIM1 Support2G/3G/4G
    SIM2 Support2G/3G/4G

    In the above link, there is a note saying:
    IMPORTANT: Both micro SIM card slots support 3G WCDMA/ 4G LTE network band. But only one micro SIM card can connect to 3G WCDMA/ 4G LTE service at a time.

    Does that mean it is still a dual active 4G+2G and not a dual active 4G+3G?

    Have you tested ZE551KL personally to see if you can have dual active 4G+3G on both SIM slots?

    The other model ZE551ML is dual active 4G+2G, but not dual active 4G+3G since second SIM slot only supports 2G.

    Reply

  47. Kevin says

    Hi Simon, brilliant article and incredibly informative. I was wondering, however, if there is any information on the technicalities of dual SIM active phones such as the software modifications and how Android OS deals with both SIMs being active?

    Thank you.

    Reply

  48. Richard says

    How about the Ulefone Armour? I understand it is dual sim; does anyone here have any experience with that phone?

    Reply

  49. Timothy says

    Thanks for the best article on Dual Sim Mobile I read so far.

    Huawei just launched a new model Mate 10 recently. There is a function switch on Dual 4G mode. Any idea what it can do? Is this phone dual active on 4G+3G or dual standby on 4G on one sim and 3G on the other?

    Reply

  50. Tetsu says

    Should this page update or remove ASUS Zenfone 2 Laser ZE551KL as a dual active phone? It is still the non-exhaustive list.

    Reply

  51. savic says

    Thanks for great article. My question is: if I use 2 sim stand by phone, and have different viber or whatsup accounts for each sim, can I use the same phone book for these applications. For example, can I use phone book from account conected to sim card 1 with viber account on sim 2?

    Thank you!

    Reply

  52. Anastasis Kokkinos says

    Hi I am looking at the galaxy note 8 duos. It says it’s a standby dual sim set up. Do you know if it works under the following scenario,

    So, dual standby Android phones may work like dual active phones when you are engaged a voice call through voLTE. In this case, if someone calls you in the other SIM card, you should get an incoming call notification as in a dual active Android phone. But you cannot put any call on-hold or on-wait, even your carrier support these.

    That would be enough for me as I don’t want one of the sims to be out of action while on a call or anything like that.

    Reply

  53. peter says

    Hi Simon,

    You should add Huawei P9 Plus VIE-AL10 as a dual sim full active phone. Indeed it’s chinese version but works great in Europe. I did not encounter any problems with i.e. google store or so on, software Its fully English except default browser. The second issue is that second sim works only as 2G.

    I bought it on eBay and I’m using it for everyday use so any question please feel free to ask.

    Reply

  54. Mido says

    Thank you for this article.. My question is what aboutnow by December 2017,,, are there any new released reliable dual active smart phones with good quality?

    Reply

  56. Tony says

    Hi, hopefully you can help. I purchased a Huawei Honor 8 dual sim card phone in Italy so I could use my US T-Mobile card and my TIM-Mobile card on both phones, everything looked like it was working ok until I came back to the states. My US card worked ok with e-mail, texting but the phone calls kept on dropping or having a lousy recption. At the TIM store they told me that it was the phone.
    Are they correct? or is there some kind of setting that probably was missed?.
    Thank you

    Reply

  58. Gatrus says

    Awesome Article !! However still confused.
    I have a business phone and a personal phone.I have tried at least 4 different dual phones and always returned them because my goal was to use both lines to make and receive calls and most importantly send and receive text messages on both lines. I obviously failed. Is it even possible?

    Reply

  59. Aina says

    Hi, thanks for the info. I need a dual call phone for work. I’ve been looking the samsung galaxy j7 or j5. Can you tell mefor sure if they are dual call?

    Thanks for your help

    Reply

  60. steve says

    S 9 and the S9+ dual sim phones.
    Do u know if they are active Sim or not. European network non carrier phone is what im after. cheers !

    Reply

  62. Frank says

    What about the Samsung galaxy a8(2018)? I read somewhere that it has an active dual sim. Is this correct?

    Thanks for the informing article

    Reply

  63. Bh says

    Dual SIM dual active has been a dream for the past 3 years for me. I currently use a Zenfone 3 which is a great phone, don’t get me wrong, but would be 100 times better if it had a second modem to support dual active. The new qualicom, mediatec etc chips technically can all support dual active, but for one reason or another the manufacturers dont make phones that way. To me it seams only logical that two Sims would have the same capability. This is the best explanation I have seen on the web yet so thank you. I hope one day dual SIM dual active will make it’s way to North America.

    Reply

  65. Andrew Grech says

    Simon hi…best thing that happened to me today is stumbling across this site. You seem to have answered my queries re dual sim (stand-by vs active (every ones dream). I have two phones, long story but i need to get back to one phone and I am considering the Samsung S9 (because iphone do not have any dual sim phones, unless you are aware of any being released shortly).

    1. Do you have any S9 guides please or does “How to use two SIM cards in Galaxy S8 and S8+?” work the same?
    2. Vodafone Malta (Europe) offers 4.5G coverage. Does this mean that both local sims (of Vodafone) will allow for simultaneous usage if set up properly?

    Also, does a dual sim phone allow the phone owner to:
    1. identify if a call / message is being made to sim 1 or sim 2?
    2. choose to call / message from sim 1 or sim 2?
    3. easily swap between sim 1 and sim 2 for data usage?
    4. store contacts on the phone thus recognise all incoming calls + easily select a contact when making a call / sending a message?
    5. easily identify messages of sim 1 and sim 2 on e.g. whatsapp or does it depend from which sim you download the App?

    Do Apps work off one sim?
    Will the Calendar App allow for double entries?

    Thank you
    Andrew

    Reply

  66. William Wallace says

    I have a work and personal phone. I use two companies, none support 2G anymore (New Zealand – Skinny Mobile/Spark Mobile). So it would be pointless buying a Dual Active Sim as one would never work.

    Just thought it might be worth mentioning, as it could quite easily be overlooked, potentially as CDMA is phased out and carriers are making the jump to 4G…

    Reply

  68. Juan Carlos says

    Excellent writing guys thanks a lot for the information. I am in the process of buying a dual sim phone, an S9+ to be clear…

    Is this phone 4G+2G or 4G+4G? All I care of is, if I get a call on SIM 1 and Im using my data on SIM 2, will the data drop untill the call is disconnected or it will remain active?

    Reply

  69. Thomas says

    Great article! How about the Huawei P20 pro? Any info on whether it’s dual active or standby? Thanks! Thomas

    Reply

  70. bigbrovar says

    Just want to say a big thank you for this post and for the dedication at answering and responding to every question asked over a 2 years period. It is rare in modern day blogging to see such level of commitment. I read through all the questions and answers and it did answer all the questions I had. I am getting the LG v20 because for me it is the best device from a price functionality and power user point of view. Although it is dual Sim standby. It has a dedicated SD card slot which does not alter the Dual Sim functionality. It is also reported to have support for a new voice band (can’t remember the name) which is not yet widely supported but at least this makes it future proof. Thanks again for all the help. Definitely subscribing to this blog. Reader from Nigeria.

    Reply

  72. mike says

    i have cut my home fiber optic 10Mb line and now rely on my phone to get internet access for my laptop via tethering/hotspot. We have a few telcos offering 4G LTE data. This works out great, not only i could save a lot of money over the long run, i feel the 4G is somehow faster than the fiber optic. A 10Mb translate to 1.25MB and a speed test on the 4G could get me around 3-5MB/s. Just one good thing about fibre line is stability, my job requires me online most of the time as i am doing ecommerce like selling on eBay, so i will have a lot of customers to serve and get their items shipped asap. The 4G is fast most of the time but sometimes like at peak hours it gets very slow and page loads forever. But this happens not very often, so is no big issue. Sometimes i need am on business trips and would get to other states. Some states maybe telco A is more coverage and faster, some states maybe telco B is faster and so on. I am actually looking for a phone with 2 sim slot which allows me to put in 2 sim cards from telco A and telco B and have both LTE data load balancing to increase data throughput and in case telco A slows down or dead due to a maintenance, telco B could still provides the data. I dun need speed increase as i never download big files, i just need load balancing and redundant feature. Is there such a phone? What is the keyword i should look for? If there is no such phone, i will need to buy 2 phones and turn on hotspot for both of them and have my laptop connected to one phone at a time and if pages failed to load i will have to manually switch to another hotspot. Or is there any WiFi Router or AP where u could insert 2 sims and give u WiFi internet? This will do too. Thank you

    Reply

  73. Richard Hadfield says

    Hi I have a OnePlus 2 phone, on a recent trip to Australia I bought a local sim (Kogan) however when this was in the phone on standby my UK sim (Tesco/O2) just wouldn’t work. I wonder if you could explain this and perhaps a way round this, regards

    Reply

  74. kjm says

    Simon, excellent posts and quick replies.
    Do u have any idea about any DSDA in Asus Zenfone 5 Series for eg. model :- ZE620KL ?

    Reply

  75. Pramod says

    Do an Duel SIM phone work with 4g/3g on First SIM + 3g on 2nd SIM? Now in Australia 2G is shut down by all carriers so 2nd SIM must connect to 3G (at least connected and showing a signal level. I am Ok if the 2nd SIM is not active during an active call on first SIM.)

    Reply

  78. Ali El-Husseini says

    Hi,
    I use Samsung S9+ Dual sim
    I have 2 sim cards , when i use the button for Dual Sim Always ON

    i get an error message saying the Following:

    Failed

    (Sim Card 1)
    Call forwarding:Failed
    Call waiting : Turned ON

    (Sim Card 2)
    Call forwarding:Failed
    Call waiting : Turned ON

    i have tried everything from disabling all kind of call forwarding
    and it never worked

    if Anyone has any suggestion it would be great

    Reply

  79. Sam says

    Simon,
    One of the best comprehensive articles/posts ever. Thank you for taking the time and going into so much detail. I was convinced the Zenfone Z5 was dual active until I read your posts. I hope a new dual active shows up soon. For now I’m sticking to two phones and hope to see one of your posts give us the good news.

    Reply

  80. J says

    Hi,

    Is there a way to make a dual sim S9 have the same radiation level as a single SIM S9?

    If I disable one sim in Android  (in settings > connections > SIM card manager > general settings > sim2 off), will this completely disable one sim radio circuit, or both sims will still keep running?

    Reply

  81. J says

    Thanks Simon!

    If everything happens in software, what causes a stand-by dual-sim phone with one sim disabled to have a higher radiation level than a single sim phone (other things, like signal strength, kept equal)? Is it that android does not really disable the second sim, it just makes it unusable?

    Reply

  83. Andrei says

    In a dual-standby scenario: Does having both sim cards on the same carrier impact the stand-by battery usage less than having them on different carriers?

    Reply

    • simon says

      No, I don’t think any Android manufacturers would launch a dual active phone this time. Qualcomm and other chip makers offer dual standby support on most of their chips. Phone manufacturers don’t need to do much work or add any cost to provide dual standby. But for dual active phones, they have to do some extra work. The additional modem, licensing fees and other hardware will cost around $10-$20.

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      Reply

      • Shrikant says

        Thanks for your reply.
        My previous query was due to a model i saw listed on an e-seller indicating it was Dual 4G Active.

        link Removed
        The RealME2 Pro phone model is listed as Dual 4g Active.

        I had been seeking a Dual Active phone since almost 10 yrs when I had an LG phone in 2006 which was indeed Dual Active that I could get voice calls on both SIM simultaneously. Since the smartphones launched in 2008 and then the Dual SIM models came out, all were Dual Standby mode as you have highlighted in this guide. Having read that this phone was mode, I was very interested in buying this as it would have helped immensly in my work.
        But before buying i even posed a query on the site to check if it indeed is the Dual Active mode that I think it would work as or the seller wrote it only for selling the product. When I read the different crudely formed responses saying it was Dual 4G Dual VolTE and to a question when I asked if it would simultaneously receive 2 calls I got a reply in the affirmative. so I went ahead and bought the phone.

        I spent ~ $180 for this phone and I am told that it is Dual Active only for 4G data. Calls will be received still only 1 SIM at a time. if one is active the other SIM will be inactive.

        To complicate things and make it easy to sell, sellers add random nouns, adjectives to specs and play to confuse the buyers. Not sure who is ethical in this game but definitely the sellers who get protection from the platforms are never ethical.

        So I am actually using this above article of Dual Active mode guide to fight my case.
        I am not sure if there is any other technicality I need to be aware of to fight this battle with the seller since the e-platform is acting in favor of the seller and are refusing to accept my request for a refund or get me a truly Dual Active phone. Such cheats!

        Reply

  86. Pete says

    Hello, thanks for the article and all the responses!
    I think I have it figured out: my current BLU phone is obviously 4G+2G only. When I enable data on SIM 1, then SIM 2 becomes unusable because there is no 2G available.

    So, I am looking at a Samsung A8, I figure it should connect 4G on SIM 1 and 3G on SIM 2. I don’t really care if data is not available while taking a call on SIM 2.

    Let me know if I have this right before I make a costly mistake!

    Thanks

    Pete

    Reply

  87. Jamez says

    Thanks for the article. I wish it was easier to find information from the manufactures whether their phones are Dual Active, Dual 4G, or Dual 4G/2G.

    My first Dual SIM phone was the Microsoft 950XL Dual, and I know first-hand how limiting a 4G/2G phone is. It drove me nuts that the secondary SIM wasn’t getting text messages.

    I used to use gsmarean.com to get information on Dual Active phones, but it seems they have changed all Dual SIM phones to Dual Standby. Not one phone is listed as Dual Active anymore.

    I used to believe my current phone, ASUS ZenFONE 3 Deluxe, was Dual Active, but since gsmarena.com doesn’t specify anymore, I don’t know what to believe.

    Reply

  88. Triad says

    All dual SIM dual active followers should right an email to Asus on EMAIL REMOVED if Asus get many emails for dual SIM dual active then Asus may manufacture Dual SIM Dual Active mobile handset.

    Reply

  92. Tom McCoy says

    I am using AT&T in the US. AT&T no longer has a 2g network. I am looking for a dual SIM phone to use with a business line & a personal line. I was thinking of the Asus Zenfone 2 (us version 4g/16g) but saw your reply about the LG V20 and am now considering it. I only use one line at a time and was going to forward one line to the other. I presently use a LG G6 and the other option is to get a inexpensive phone & just forward that line to my G6. What are your thoughts? Thanks for your article it was very informative.

    Reply

  94. Abdul says

    is it possible to disable gprs, edge and 2g on a sim card? I wan to use a sim for voice and another sim for data. In the UK, o2 is the best network for voice, and EE is the best for data. I want to use EE for data but disable all the data connection that require exclusive access to the receiver so that it does not block access to the voice sim.

    Reply

  95. Apps Patil says

    Sir plz tell me Redmi note 7 pro & samsung, m 30 which is dual sim active phone …?
    Mean in case one sim engage in
    Call then another sim call
    Coming
    .??

    Reply

  100. PP says

    Ive always had 2 phones for this reason because it was so hard to find a phone that both lines could be operational at the same time or at least be able to get a call while on a call or send text and mms while on a call.

    I couldve sworn the OnePlus 6 had Dual Active LTE Data Sim slots?
    I have a ASUS ZENFONE 6 and it has Active Dual LTE slots.

    My Samsung Note 8 does not have Dual Active LTE slots, its quite annoying. It reverts to 3g or 2g but 2g is just about gone if not already and 3g will be probably be gone by 2022.

    Do you know any current phones that have Dual Active sim slots for 4G? Maybe the new 5G phones will?

    Reply

  101. Pj says

    So ive been on this quest to find dual active sims for 3 years.

    I was told the the one plus 6T does have 2 modems and is dual active sims. I do know it has 2 modems but i do not know if they are simultaneous active 4g/3g sims or VOLTE

    Also I had a Panasonic FZ-X1. This I believe has 2 seperate modems as well. However it was a slow phone and I can’t remember testing it to see if it had Dual Active 4g sims or not.

    The Asus Zenfone 6 and Samsung note8 are only dual standby.

    The newer iphones with esim are only dual standby sims as well.

    Oneplus says the new 8 pro and 8T will have dual active sims in a future update but that had been said for 6 months now and still no dual active or even a second sim at this point.

    If anyone can guide me to a the 3 latest newest phones with dual active sims, it wpuld be greatly appreciated!

    Thank you for the great article!

    Reply

  102. Brian Byrd says

    Clearly YOU DO NOT WORK FOR AT&T, thank you very much for taking the time to explain this, even a while back, this info still applies and the phone companies are not training their people, they are simply selling you products.
    Over a week dealing with them, sold 2 different devices for dual sim dual active, with simple explanations of what I want to achieve – one phone two numbers, active at the same time.
    Neither device worked as advertised by the sales people – BEWARE, they will attempt to charge you a restocking fee on a return, NO WAY is that acceptable when they sell you something that doesn’t work, just be aware that’s a sales tactic.

    Reply

  103. Nitin Pandit says

    I have a Samsung A50. Is it DSDS or DSDA?
    Also… if I place one SIM in the default mobile data mode, will the phone receive mobile data via the second SIM?

    Reply

  104. upidupi says

    Mate 8 is DSFA (dual sim full active): one of flagship DSFA.

    I own two mate 8 one 3GB + 32Gb and one 4GB + 128GB

    Reply

  106. S P Arif S Wibowo says

    How can we tell that a phone is a dual-4G? For me this is a more important concern since one of my carriers is 4G only (AWS), while from the other carrier I will need the 4G data. With DSDS forwarding it to a VOIP phone service with its app in the phone can be good workaround.

    More specifically, is Google Pixel 4a is dual 4G? As per Google, Pixel 4a is DSDS if one of the SIMs is an eSIM.

    Reply

  107. S P Arif S Wibowo says

    Thanks for replying!

    Good to hear that most mainstream dual SIM phones – especially with Qualcomm chips – support dual 4G. Still, nice if we canto confirm that before purchasing the phone. Where can get the spec sheet that contain that information?

    I look into GSMArena and PhoneArena and neither has it, GSMArena does not even explicitly say whether the phones I checked are dual SIM. However, they do say what the chips are. For Pixel 4a, the chipset is Qualcomm SDM730 Snapdragon 730G, and its spec in Qualcomm site says “Multi SIM: LTE Dual SIM”. Is this the key information? Seems like Qualcomm has this for long since even Snapdragon 821 – which runs original single-SIM Google Pixel – also has “Multi SIM: LTE Dual SIM”.

    – https://www.gsmarena.com/google_pixel_4a-10123.php
    – https://www.phonearena.com/phones/Google-Pixel-4a_id11311
    – https://www.qualcomm.com/products/application/smartphones/snapdragon-7-series-mobile-platforms/snapdragon-730g-mobile-platform

    Reply

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