Long Reef

Long Reef is a natural barrier reef on the ocean-facing side of Biscayne National Park, reached by boat. The National Park Service lists three Long Reef moorings at charted depths of 59, 56 and 51 feet. Those points mark access to the reef, not its full outline.

Plan this as a boat dive, not a shore visit. Moorings can be damaged or missing, so have an alternate plan before heading out. The park allows boats up to 45 feet to use a mooring (unless specifically authorized otherwise) for up to four hours. Approach at idle speed and watch for swimmers. If anchoring, stay at least 300 feet from mooring buoys and set on sand downwind of the reef, with the line clear of coral.

A dive guide groups Long Reef with Biscayne’s ocean-side barrier reefs and describes coral-encrusted ridges and grooves running toward sandy bottom. It’s a drift-style underwater landscape rather than a single lookout. The 51–59-foot figures are depths at the named moorings, not a complete profile of the reef; a reported approach toward 100 feet describes this broader reef group and isn’t a depth guarantee for each mooring.

If you’re taking an underwater photo, frame across a ridge and its sandy groove to show the reef’s shape. A close view can show coral texture, but it won’t tell the whole story of the underwater terrain.