Apple Watch Series 9 not receiving calls when away from IPhone

A cellular Apple Watch will have a Red circle ⭕️ around the Digital Crown. A GPS Only will not.

If you do have a Red circle ⭕️ on your Digital Crown, then did you sign up for Apple Watch support with your iPhone carrier. The following carriers support the iPhone and Apple Watch number sharing

Apple Watch - Carriers - Apple

And even if you have a Cellular Apple Watch, and the cellular enabled by your iPhone carrier, you will still need your iPhone powered on and able to access the Internet (even if it is still at home), with both the iPhone and Apple Watch signed into Apple's Messages, if you wish to send and receive SMS/MMS TEXT messages.

SawSashi wrote:

I do have a cellular watch. I will need to call ATT for help, I suppose.

Yes. Work with AT&T.

Also if your issue was Yesterday (Friday, 23-Feb-2024), be aware that AT&T had a nationwide service outage for a few hours 😱

The GPS-only Watch makes and receives phone calls through the paired iPhone which must be nearby. Only the GPS+Cellular Watch can make and receive calls independent of the paired iPhone.

Which watch did you buy?

M1 Mac mini, macOS 14.3.1;  Watch, series 7 GPS/cellular, watchOS 10.3.1; iPhone 12 Pro, iOS 17.3.1; TV 4th Gen, tvOS 17.3; HomePods, audioOS 17.3 and Airport Express w/ Airplay 2