One other thing to consider is the size and shape of the SIM required for your phone. Make sure you get a nano-SIM if a nano-SIM is what your phone requires. For the record, every phone in this list takes a nano-SIM. If you get that wrong it is easily solvable; every network will gladly send over a different-sized SIM. SIM cards tend to come in all three sizes, you simply pop out the one you need. But that's assuming you are getting a new SIM, and if you're looking for a SIM-free phone or unlocked phone you probably already have one. More important is to make sure that if you want 5G you get a 5G-enabled phone and SIM.