Baie Rouge
Baie Rouge is a small, quiet beach on the north side of the western end of St. Maarten. It's lies just to the east of Plum Bay, on the French Side. It is one of the clothing optional beaches on the island, especially on the western end.
You will find a few amenities available here, including some local vendors that sell food and drinks. There are also chairs and umbrellas for rent, and also snorkeling gear.
The water is usually fairly calm, which makes it a nice beach for swimming. There are rocks at the eastern end which will probably be the best bet for snorkeling, since the rest of the beach is just smooth white sand.
If you like walking along beaches, enjoying the sand and ocean or the people, Baie Rouge is a great place to visit. This beach is quite long and will give you hours of meandering enjoyment.