Sosua Bay is widely regarded as one of the better dive destinations on the Dominican Republic's north coast, with coral reefs, a small wreck, and walls that descend to 30 metres or more. The best snorkel and dive site, locally known as the Canyon or Los Cabezos, sits in the bay and features coral walls, sponge gardens, and a reliable cast of reef fish. Visibility is typically 20–30 metres in good conditions.
Several dive shops operate from the beach and along the main strip, offering single dives, PADI certification courses, and multi-day dive packages. Sea Pro Divers is one of the most established operators. Conditions are generally good year-round, though the winter months (November to April) bring steadier trade winds and occasional chop on the surface. The marine life includes moray eels, nurse sharks, eagle rays, and the usual Caribbean reef fish. Snorkellers can access the shallower parts of the reef directly from the beach.