What to do if iPhone is lost or stolen at the beach?

In the unlikely event that the iPhone was simply lost and an honest person picked it up.......check with the Lost & Found.....if there is one at the beach.

Otherwise, realistically the iPhone was likely stolen. Follow the instructions in the Apple Support document linked below:

https://support.apple.com/en-us/101593

This may help --> Do's and Don'ts for lost iPhones - Switch… - Apple Community