You take a ferry to St. John and get to do what you want I wish the ferry went back and forth more often we did not have a alot of time for the island because the ferry went back at certain times.
We did snokeling under the pittons it was so much fun! The crew on the boat we took the pittons played music gave us rum punch on the way back it was like a party on the boat! we loved it!! we saw an underwater snake lots of fish, saw the volcanoes