I spotted this little gem an Apple help page discussing things you can do with your Apple Watch over Wi-Fi:
- “If your Apple Watch is in range of a Wi-Fi network that iPhone has connected to before, you can still do the following (even if iPhone is turned off): Make and receive phone calls (if you have Wi-Fi calling enabled and you’re within range of a Wi-Fi network that your iPhone has connected to before)”
Wow! Let’s say you leave your iPhone at the office, then you can STILL use your iPhone at home to make calls provided the Watch is within range of a Wi-Fi network that your iPhone has logged into before.
However, this is only possible if your cellular provider (a.k.a. “mobile company” if you’re British) has enabled Wi-Fi calling. Here in the UK that’s just EE at the moment, while in the US AT&T, Sprint, and T-Mobile users should be good to go (Apple has a support page listing providers worldwide).