I would recommend Megans Bay in St. Thomas. It is beautiful. We opted for a tour but you can take a cab (there are plenty) and enjoy the beach. They have a little snack bar and you can also rent beach chairs. It was voted one of the top ten beaches. I don't think you will be disappointed. For St. Maarten we didn't go to any beach, should have!! However the guy we were with took us by car around the island. If ever there again we would opt for the beach scene. Enjoy your cruise.