While you are cruising on huge cruise ships, you'll visit many ports of call. There are many choices of activities while in those ports both ashore and on the water. Here are some images of some of the choices of water excursions.
Ah, yes, a day on the water.
The Best of St. Thomas and St. John, U.S. Virgin Islands (Best of St. Thomas & St. John, U.S. Virgin Islands)