Hi
Once your iPhone has adjusted to a new time zone - and, if appropriate (such as after being placed into Airplane Mode during travel), your devices have reconnected via Bluetooth - the time on your Apple Watch should adjust automatically to reflect the time on your iPhone.
If that is not happening as expected, then the following steps may help (check after each):
If you have not yet done so, update your iPhone and Apple Watch to the latest software, starting with your iPhone:
On your iPhone, go to: Settings > General > Date & Time > check that Set Automatically is selected.
On your iPhone, go to: Settings > Privacy > Location Services:
- Check that Location Services (the main setting at the top) is enabled.
- If the setting is already turned on, try turning it off, pausing for a few moments and then re-enabling it.
- In the list of apps beneath, check that Apple Watch Faces is set to While Using.
- Toggling the setting to Never and back again may help.
- At the bottom, tap on System Services > check that Setting Time Zone is enabled (you may also wish to enable all other system services, if they are not presently enabled).
Check that Bluetooth and Wi-Fi are both enabled on your iPhone:
- iPhone: Settings > Bluetooth - on.
- iPhone: Settings > Wi-Fi - on.
- For the best performance from your watch, keep both Bluetooth and Wi-Fi permanently enabled on your iPhone.
Check that your Apple Watch is connected to your iPhone via Bluetooth:
The following further steps may also help:
Restart both your iPhone and your watch, turning both devices off together, then restart your iPhone first;
Unpair and re-pair your Apple Watch again: