Apple Watch battery drain

Hi Jonny

The following steps have helped to resolve issues with battery life for some users:

Restart both your iPhone and watch. Turn both devices off together, then restart your iPhone first:

• To turn your watch off: press and hold the side button until you see the Power Off slider; drag it to turn off.
• To turn it back on: press and hold the side button until you see the Apple logo.

If that does not help, next unpair and re-pair your watch:

• The Watch app on your iPhone takes watch backups automatically, including a fresh one when unpairing. When setting it up again, choose to restore your watch from backup when offered the option. Most data and settings will be restored, with some exceptions (eg Apple Pay cards, passcode).
• Unpair your Apple Watch and iPhone - Apple Support
• Set up your Apple Watch - Apple Support

For the best performance from your watch, keep both Wi-Fi and Bluetooth permanently enabled on your iPhone.

If you have not yet done so, it may also help to update your iPhone and watch to the latest software.

Instructions for updating each:

• Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
• Update the software on your Apple Watch - Apple Support

If you have been using a third-party app (eg Strava) to record workouts, check whether there is presently a paused activity within the app. If there is, end the activity.