I FOUND A APPLE WATCH IN THE OCEAN but its locked by original owner

Activation Lock is designed to prevent anyone else from using an Apple Watch if it's ever lost or stolen.

About Activation Lock on your Apple Watch - Apple Support

Activation Lock is an anti-theft feature that cannot be bypassed. Only the previous owner can remove the lock by using their Apple ID & password. Apple will not help you find the previous owner. If the previous owner cannot or will not remove the lock, then the watch is useless to you or anyone else. Turn it over to the authorities or dispose of the watch properly.

Only the original owner can unlock that Apple Watch. You will not be able to use it. This feature stops the illegal use of someone else’s device. The best thing to do would be to turn the Apple Watch over to the local lost & found or to the local authorities. I’m guessing someone is looking for that watch.