When you are in St. Thomas, I would suggest going over to St. Johns and do some snorkeling. There are quite a few beaches there that are good, I truly loved Trunk Bay, they have a snorkeling trail underwater that is impressive, plus you can snorkel around a small island. This does require some travel time, you need to take a cab to Red Hook ferry, then after the ferry ride, another cab to a beach. So, if you have the time, it is a well worth trip.