St. Barths is a popular yachting and sailing center, thanks to its location midway between Antigua and St. Thomas. Gustavia's harbor, 13 to 16 feet deep, has mooring and docking facilities for 40 yachts. There are also good anchorages available at Public, Corossol, and Colombier. You can charter sailing and motorboats in Gustavia Harbor for as little as a half day. Stop at the Tourist Office in Gustavia for an up-to-the minute list of recommended charter companies.
Marine Service (Gustavia. 0590/27-70-34. www.st-barths.com/marine.service) offers full-day outings, either on a 42- or 46-foot catamaran, to the uninhabited Île Fourchue for swimming, snorkeling, cocktails, and lunch. The cost is $100 per person; an unskippered motor rental runs about $260 a day.
Yellow Submarine (Ferry Dock, Gustavia. 0590/52-40-51. www.yellow-submarine.fr) takes you "six feet under" (the surface of the sea) for a close-up view of St. Barth's coral reefs through large glass portholes. Once a week you can go at night. It costs EUR 40 for adults and EUR 12 for kids under 12. Trips depart hourly starting at 9 AM.