The reefs around Praslin are among the best in the Indian Ocean for snorkelling. The water is warm year-round, visibility is typically excellent, and the marine life is extraordinary: over 900 species of fish have been recorded in Seychelles waters, along with hawksbill turtles, green turtles, whale sharks (seasonal), reef sharks, rays, and enormous Napoleon wrasse. The best snorkelling beaches on Praslin itself are Anse Lazio (north reef), Anse Georgette, and the beaches around the southwest tip.
For diving, the offshore sites add depth and drama. The Shark Bank is a submerged granite plateau about 20 minutes from Praslin by boat, where grey reef sharks and silky sharks congregate and whale sharks pass through between October and March. The Channel between Praslin and La Digue has strong currents and correspondingly dense fish life. Several dive operators run from the main jetty at Baie Sainte Anne, and courses and equipment rental are available.