It's matter of the heart. Why do we go to the beach in the first place? I go to enjoy the water, the outdoors, and sunshine (all created by God for our enjoyment)."It is a sin to go to the beach!"
If I go to secretly admire sunbathers, then that is another matter. As we men are fully aware, lust is not limited to the beach.
Since about two-thirds of the American population is now considered over-weight or obese, the temptations may not be there to start with.

Enjoy you summer!!