If you use iCloud Backup on your iPhone and you had paired your Apple Watch to your iPhone then an automatic backup would have been created when you last unpaired your Watch.
If you use iTunes then it will also create an automatic backup but it will only include all of the data of the backup if iTunes Backups are encrypted.
After unpairing your Apple Watch, you can restore it from your iCloud Backup by pairing it again to your iPhone. To restore your Apple Watch using an iCloud Backup, follow the steps below:
How to restore Apple watch from an iCloud Backup:
- Tap on the Watch app from your iPhone.
- Tap on Start Pairing if no watches are paired. Tap on your current Watch and if you want then you can pair the second watch too.
- Once your watch has been paired, tap on Restore from Backup.
- Select the backup from which you would like to restore your Apple Watch.
The whole process will take a little while to complete. While the backup is in the process, make sure that your iPhone and Apple Watch are as close together as possible.
After the process completes, you Apple Watch will be restored from the backup that you selected.