Using Apple Watch independently of iPhone

[esm1]

I am considering buying an Apple Watch SE with the built-in cellular option.

My question is: Once properly set-up with an O2 plan, can the Apple Watch cellular be used fully independently of my iPhone? i.e. Can I leave my iPhone turned off at home and use the Apple Watch to make/receive phone calls while out and about?

[MI5]

@esm1 

That's how it is supposed to work but quite a few have issues getting setup properly with O2.

[esm1]

Thanks for your reply. I just read that some networks need the iPhone to be ON (even when not near the Apple Watch) for the cellular function of the watch to work.

[MI5 · Accepted solution]

Only on Android phones with O2 @esm1