Find device will work even though the Apple Watch is not power on?
My Apple Watch is not power on . Can I still locate my Apple Watch?
Apple Watch Series 7, watchOS 8
Question marked as
Yes you can, as long as turn on last location is on you will be able to see the last location your device was when it was on. if you weren’t able to find it then you can refer to this link to help guide you in your search.
If your Apple Watch is lost or stolen - Apple Support