Most of the French side beaches are ok with naturism, there is only one official naturist beach ”la Baie Orientale” but on the French side no one really mind about naked people. So, it s just a question of logic. You can go everywhere if you stay away from the family spot. The Dutch side is a bit more puritan, don’t go naked anywhere you will have troubles, but don’t worry, there is still some spots to relax naked.
La Baie Orientale (Oriental bay beach) the beach is the only official naturist beach of Saint-Martin. There is not much shade there, so bring your umbrella, it s a long and beautiful beach of white sand with nice waves, a nice and familial beach to spend the day. Le “club orient” (naturist resort) use to be there but since a hurricane, the resort is close. The naturist beach remain and it s an easy spot to go with an amazing view on the turquoise bay.