Flat Island Reef

Flat Island Reef sits off the eastern tip of Saint-Martin's French side, a submerged plateau extending from the uninhabited islet with pristine coral formations rarely visited by divers due to its more exposed location requiring settled seas. The reef top at 8–15 m is carpeted with star corals, brain corals, and sea plumes, while the deeper edges shelter goliath grouper, large barracuda schools, and the occasional Caribbean reef shark. Strong surge on windward days keeps the corals exceptionally clean and well-oxygenated, supporting some of the island's most intact soft coral gardens.