An archipelago of granite and coral islands in the western Indian Ocean, Seychelles is best known for the sculpted granite-boulder reefs of its Inner Islands around Mahe, Praslin and La Digue, where divers find seasonal whale sharks, reef sharks, eagle rays and turtles, plus the wreck of the 270 m tanker RFA Ennerdale.
Destination info
Conditions, highlights, and the resident marine life.
Conditions
Water and air temperature across the year.
WaterAirDryShoulderWet
Description
The diving heart of Seychelles is the Inner Islands granitic group around Mahe, Praslin and La Digue, where the same weathered granite that forms the islands' iconic boulder beaches continues underwater into pinnacles, swim-throughs and rounded outcrops draped in soft coral and fire coral. Conditions are governed by the monsoon: the northwest monsoon (roughly December-March) brings warm, calm but sometimes rain-stained water, while the southeast trades (May-September) drive swell against the southern and western shores and push nutrient-rich water that fuels plankton. The two inter-monsoon transitions, April-May and October-November, deliver the year's flattest seas, warmest comfort and best visibility (often 25-35 m at offshore sites). Whale sharks (Rhincodon typus) aggregate off Mahe with a peak in August-October, an event monitored for decades by the Marine Conservation Society Seychelles. Reef manta rays (Mobula alfredi) have been photo-identified across six of the seven island groups, though reliable aggregations now centre on the remote outer Amirantes (D'Arros and St Joseph) rather than the Inner Islands. Hawksbill and green turtles are everywhere, the country hosting the western Indian Ocean's largest nesting hawksbill population. Far to the southwest, the UNESCO World Heritage atoll of Aldabra (1,100+ km from Mahe) offers near-pristine reef diving reachable only by special-permit liveaboard expeditions.
Highlights
What makes this dive worth the trip.
Whale sharks (Rhincodon typus) aggregate off the main island of Mahe with the presence temporally and spatially limited and a peak in occurrence during August-October; the Marine Conservation Society Seychelles has run scientific monitoring of the aggregation since a pilot programme began in 1996.
Diving conditions follow the monsoon cycle: the northwest monsoon (December-March) is warm and calm, the southeast trades (May-September) bring swell and lower inner-island visibility, and the two transition windows of April-May and October-November give the flattest seas and the best visibility (around 25-35 m at the better sites).
Reef manta rays (Mobula alfredi) have been photographed within six of the seven island groups of Seychelles, with 64% of identified individuals resighted at least once between 2006 and 2019, though the most reliable aggregations are now at D'Arros Island and St Joseph Atoll in the outer Amirantes rather than the Inner Islands.
Marine life
37 species you’re likely to encounter on a dive here.
Dive sites
5 signature sites at this destination.
Shark Bank
A large granite pinnacle rising from the seabed roughly 8 km northwest of Mahe, between Mahe and Silhouette, and the signature offshore dive of the Inner Islands. The rock and its surrounding plateau sit between about 18 and 30-35 m and gather very abundant reef fish, schooling yellow snappers and jacks, large stingrays and eagle rays, nurse sharks resting on ledges, and occasional passing whale sharks. Because it is exposed and tidal, it is best dived around slack water and is usually run as an Advanced Open Water site.
18–35 mintermediateDay boatModerateVisibility 15–30 m
Brissare Rocks
Two small granite islets standing in open water north-northeast of Mahe, about 40 minutes by boat from Beau Vallon, smothered in fire coral and surrounded by dense shoals of fish. Divers work the boulders between roughly 8 and 20 m, finding snappers, fusiliers and jacks, white-tip and nurse sharks, Napoleon wrasse, eagle rays and hawksbill turtles, with whale sharks possible in season. It is a great shoal-and-big-fish site when conditions allow, but exposure to wind and current can close it.
8–20 mintermediateDay boatModerateVisibility 10–25 m
Ennerdale Wreck
The wreck of RFA Ennerdale, a roughly 270 m British naval oil tanker that struck an uncharted granite pinnacle and sank fully laden in 1970 about seven miles off Port Victoria. The hull is broken into sections, but the stern with its huge bronze propeller and accessible pilot house is largely intact and offers straightforward penetration for experienced divers. Now an artificial reef, it draws shoals of yellow snappers, morays, scorpionfish, groupers, batfish, leopard and common stingrays, nurse sharks and the occasional whale shark.
20–30 madvancedDay boatModerateVisibility 15–30 m
Baie Ternay Marine National Park
A sheltered bay at the northwest tip of Mahe, about 20 minutes by boat from Beau Vallon, protected as a marine national park with active conservation enforcement. A gently sloping hard-coral reef and wall run to around 20-23 m over seagrass beds that are important turtle feeding grounds. It is the most beginner-friendly of Mahe's sites, with hawksbill and green turtles, white-tip reef sharks, octopus, moray eels and a wide range of reef fish, and is a common check-dive and training location.
5–23 mbeginnerDay boatLightVisibility 5–15 m
Dredger Wreck
A purpose-relevant wreck lying on its side in roughly 20-30 m of water near Mahe, popular as a deeper wreck dive for Advanced Open Water divers. The structure has become an artificial reef colonised by encrusting growth and gathers schooling reef fish, with morays, lionfish and stingrays among the resident life. It pairs well with the nearby offshore granite sites on calmer transition-season days.
20–30 madvancedDay boatModerateVisibility 15–25 m
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