Configuring cellular on new SE watch from someone else's phone plan

[TomGolden]

I searched for a bit and didn't find any articles that seem to address this rather unusual scenario. Highlights are as follows:

* My sister has AT&T as her mobile phone provider
* I have T-Mobile as my mobile provider
* My sister just got a "buy one, get one free" deal on a new Apple watch SE model from AT&T, so she sent me the 2nd watch.
* This watch is tied to her mobile phone plan (AT&T) for the phone number and monthly payments

I am trying to go through the setup on the watch to pair it to my iPhone 7Plus (latest iOS), but I can't get the cellular part to configure correctly, I believe because my phone is a T-Mobile device while the watch is on her AT&T plan.

Everything else about the watch and pairing with my phone is working perfectly, but I am hoping I can get the cellular part to work as well.

Does anyone have any suggestions, or am I SOL?

Much appreciated,
Tom

 

[bricktop_at]

The watch has to be configured to the same provider and number you use for the iPhone

Set up cellular on Apple Watch - Apple Support

With a cellular connection on Apple Watch, you can make calls, reply to messages, receive notifications, and more — even while you’re away from your iPhone.

support.apple.com

 

[TomGolden]

That's what I suspected and was afraid of. Much appreciate the quick response.