Of course, you can use Galaxy S20 without a SIM card (you can use WiFi/Bluetooth/USB for connections). But it does not make sense to buy a Galaxy S20 if you plan to use it without a SIM card. You can get a WiFi-only tablet at a far cheaper price.
This Galaxy S20 guide explains the size of the SIM card on Gallaxy S20, possible configuration for the SIM card tray, how to use the SIM card on Galaxy S20 with or without a micro SD card, and how to use two SIM cards and eSIM on Galaxy S20.
The detailed explanation of eSIM support on Galaxy S20 can be found here.
What is the SIM card size on Galaxy S20?
Like most other phones released in recent years, Galaxy S20, S20+, and S20 Ultra all use nano-SIM cards only.
A nano-SIM card is the smallest one among the 4 possible SIM card sizes for mobile phones:
Most carriers now issue 3-in-1 SIM cards (as shown below). In this case, you can detach the largest part as a mini-SIM. Then you can get a micro-SIM card from the mini-SIM. A nano-SIM card can be detached from the micro SIM card.
You should keep the “waste” because they can be used as an adapter for micro-SIM (from nano-SIM card), or mini-SIM adapter (from micro-SIM). Some old tablets and MiFi (mobile router) may still require a larger SIM card.
If you are using a phone bought within the last 10 years, very likely, the phone is using a micro SIM card or a nano-SIM card.
It is possible (and simple) to trim a nano-SIM card from a micro-SIM card. But it is recommended to do it in the handphone shop using a properly-sized clipper. Do not use scissors.
Here is a list of some popular phones that use nano-SIM card already. If you want to migrate to Galaxy S20 from these phones, you can keep using the existing SIM card.
- Samsung Galaxy S6, S7, S8, S9, S10 and all their variants (e.g., S10, S10+, S10e, S9, S9+, S8, S8+, S7, S7 Edge, S6, S6 Edge, and S6 Edge+).
- Samsung Galaxy Note 5, Note 7 FE, Note 8, Note 9, Note 10, Note 10+,