Is this a joke? Most mechanical watches, Rolex, Panerai, for example started as diving watches. They're made specifically FOR the water. What does cost have to do with anything? How do I know what time it is when I'm swimming in the ocean with my kids all day?
The better question is who DOESN'T wear a watch at the beach.
I don't wear a watch at the beach. What for?
We use the old sundial, tide flow or out of alcohol method.