Originally Posted by
TGarza
With my iPhone 15, there is an option to turn off cellular data to restrict all data to WiFi if only one sim is active. Offline maps still work since the phones are GPS capable without cellular data.
I think that was added by an iOS update somewhere along the way; my XR has it too but it definitely didn't used to be there.
AFAIK you still can't switch off your SIM altogether if you only have one, though you can definitely switch off all your SIMs if you have at least two. I'm not going to delete my eSIM collection to find out
edit: my work iPhone 14 (iOS 17) has only one SIM and indeed there's no toggle to switch it off altogether.