St. John has a half dozen good dive sites off its southeastern shore, as well as two good sites just off Cruz Bay . The string of cays between St. John  and St. Thomas —from Carval Rick to Thatch Cay—is also popular with divers. The Maj. Gen. Rogers, a 1940 army freighter, was sunk in 1972 to become an artificial reef. The excellent reefs around Grass Cay and Mingo Cay are good for beginning divers. There is a dizzying array of sealife at Witch’s Hat on the southern tip of Steven’s Cay, just off Cruz Bay.
South shore dives include Cocoloba, an easy, sandy reef dive, and Maple Leaf, a large offshore reef east of Reef Bay . The most famous east end dive site is Eagle Shoal, between Ram’s Head  and Leduck Island. The shoal, known for its massive underwater cave, has been the site of underwater weddings. Access to Eagle Shoal is limited due to its exposure to southeasterly swells.
Low Key Watersports (Cruz Bay, 340/693-8999) offers daily dive trips as well as certification courses. Captain Bob Carney leads dive trips with Paradise Watersports (Caneel Bay Resort, 340/779-4999, www.paradisevi.com ), which specializes in small groups. Cruz Bay Watersports (Cruz Bay and the Westin Resort, 340/693-8720) departs from the national park dock in Cruz Bay . Its office is located below Chilly Billy’s in the Lumberyard Complex. Maho Bay Watersports (340/776-6240) at Maho Bay Camps offers certification, resort courses, and a regular schedule of one- and two-tank outings.
Dive rates vary, but expect to pay about $60 for a single-tank dive and $90 for a double-tank dive. Discover Scuba courses, also called resort courses, which give inexperienced divers a brief introduction to the sport, run about $85 and include one shallow reef dive. Many dive shops offer economical packages of multiple dives for scuba enthusiasts.