no mobile coverage draining battery

Put the phone into Airplane mode. When there is no signal the phone attempts to find a cellular network every few minutes by sending a “Hello, are you there?” transmission at the highest power it can, in the hope of being heard.

You can still use Wi-Fi in Airplane mode, and you can even make and receive phone calls if you have Wi-Fi calling enabled.

And this behavior is not unique to the iPhone either, all cell phones do this.

I live up in the Sierra Nevada mountains where cell coverage is very spotty. Pretty much everyone who lives up here is forced to use Wi-Fi calling from home in order to avoid the significant battery draining searching behavior described earlier in this thread.

Definitely something to keep in mind when you're traveling and unfamiliar with the local area you are in.

Especially if you're running exclusively on battery and you don't know where your next charge is coming from. 😉

001mikey100 wrote:

Should I have gone e sim? Do emergency calls require a physical sim?

and if so …. Can I switch back?

eSIM or physical SIM is not going to make a difference in your cellular signal. Emergency calls can be made with either type of SIM if you have a cellular signal or WiFi calling.

Whether or not you can use a physical SIM depends on your carrier and where you bought the phone. If you bought it in the U.S., it doesn't support physical SIMs.

You don’t need a physical SIM for emergency calls. You actually don’t even need a SIM if the phone has been activated on any network at least once. A true emergency call to an emergency service is required by law to be carried by every carrier. And if you have an iPhone 16 purchased in the US it has no place to insert a physical SIM.