You may want to can perform a Factory Reset on your Galaxy Watch to make sure all of your personal data is removed from the watch. It will wipe everything clean and set the watch to its default settings, so you won’t have to worry about personal data still being on it.
Resetting your Galaxy watch
Perform the following steps in order-
Total Time: 3 minutes
Turn your Galaxy Watch off.
To do so, press and hold the Power/Home button at the bottom of the Watch face.
Keep pressing them until Rebooting appears at the bottom of the watch face.
Quickly, keep pressing the Power/Home button many times until the Select REBOOT MODE screen appears.
Press the Power/Home button to scroll through options.
Press and hold the Power/Home key until the device starts to reboot.
The watch will now start the process of deleting data. This can take several minutes. That’s it, you’re done!