Neutrogena makes an ultra sheer, dry-touch sunblock SPF 70. They also make Baby Face sun screen 50 that's water proof. If it were me I would not chance it. It can take up to a year for the spot where the mole was to heal 100%. The sun can do damage. It's fresh new skin that is very sensitive to the sun. I'd wear a hat too.

They have small water proof bandaids in a circle shape that might hold up in the water. I'd bring extra in case they don't last long.