If you enjoy sailing, the Random Wind is a great trip. It lasts all day, includes breakfast, lunch, snacks, drinks, and three snorkeling stops. As has been said, snorkeling in St. Maarten is not as good as other Caribbean islands, but still fun. Random Wind limits the number of participants, so the sailing part of the trip is more relaxing than on an overly crowded catamaran.
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The Friendly St.Martin Island Forum