Whenever your Apple Watch cannot connect to the paired iPhone via Bluetooth, it will attempt, as a fallback, to connect to a compatible Wi-Fi network.
A compatible Wi-Fi network is an 802.11b/g/n 2.4GHz Wi-Fi network that your iPhone has connected to before whilst your Apple Watch was connected to the iPhone via Bluetooth. Apple Watch cannot connect to 5GHz Wi-Fi networks or to public networks that require logins, subscriptions or profiles.
To check whether your Apple Watch can connect to Wi-Fi:
- Enable Airplane Mode on your iPhone:
- On your Apple Watch, open Control Centre (when viewing the time, swipe up on the screen) and check for the Wi-Fi symbol at the upper-left of the display:
If your Apple Watch does not connect to Wi-Fi as expected (after allowing a few moments), then follow these steps:
If you have not yet done so, update your iPhone and Apple Watch to the latest software, starting with your iPhone:
- Update the iOS on your iPhone, iPad, or iPod touch - Apple Support
- Update your Apple Watch - Apple Support
Firstly, ensure that your Apple Watch and iPhone are connected via Bluetooth and also that your iPhone is connected to your Wi-Fi network:
On your iPhone, go to: Settings > Wi-Fi:
- Tap on the "i" / info icon to the right of your Wi-Fi network name > tap on Forget This Network.
- With your Apple Watch still connected via Bluetooth, reconnect your iPhone to your Wi-Fi network, being sure to check that you are connecting to an 802.11b/g/n 2.4 GHz network.
- Pause for a few moments to allow the Wi-Fi information to be shared to your Apple Watch.
On your iPhone, enable Airplane Mode:
Check whether your Apple Watch has successfully connected to the Wi-Fi network by checking for the Wi-Fi icon at the upper-left of Control Centre (allow a short while for it to connect after losing the connection with your iPhone):
When finished, turn off Airplane Mode on your iPhone.
If you have not yet done so and if the feature is supported on your plan, you may also wish to enable Wi-Fi Calling on your devices:
- On your iPhone, go to: Settings > Phone > Wi-Fi Calling.
- On your iPhone, in the Watch app, go to: My Watch > Phone.
- Make a call with Wi-Fi Calling - Apple Support
If the issue persists, then I suggest that you contact Apple Support (remote diagnostics and/or mail-in service may be available, if required), make a Genius Bar reservation or visit an Apple Authorised Service Provider for assistance: