Delta Shoal

Delta Shoal is a shallow reef and wreck site off Marathon in the Middle Florida Keys, featuring a flat coral reef and sand flats studded with large elkhorn and brain coral heads and deep coral canyons. The site is centered on coral gardens and shallow wreck fragments, offering an easy, scenic experience popular with snorkelers and beginner divers. Dives are boat entries with routes that typically drift slowly over the reef flat from one coral garden or wreck debris pile to another. Depths range roughly from 6 to 25 feet, currents are generally light, visibility is often excellent (30–100 feet), and water temperatures are warm year-round, generally in the mid-70s to mid-80s °F. The bottom is sand with scattered coral outcrops and patches of turtle grass; there is no significant overhead or technical requirement. Boats should avoid anchoring on the reef and divers must take care not to damage fragile corals. The reef contains remnants of several historic wrecks, including the 1842 three-masted merchant ship North America, which carried dry goods and furniture, a locally named sunken barge at the eastern end of the reef, and the so-called Ivory Wreck, an 18th/19th-century vessel that ran aground and was named for ivory tusks in its cargo; wreck timbers and debris are scattered across the shoal.