Seasons & Conditions
Diving is possible all year round but is governed by an island’s position and the prevailing winds. Generally speaking, the best conditions for both the Inner and Outer Islands are in the calm periods, April-May and October-November, when the water temperature can rise to 29ºC and offers excellent (up to 30 metres) visibility.
In December and January, the north-west winds blow but conditions remain much the same as in the calm periods, with the exception of greater surface movement and some localised turbidity.
From May to September the winds are stronger and blow south-easterly. Visibility and temperature may thus drop during August with water temperatures of around 25°C. A wet suit of at least 4mm is necessary.
Unlike the Inner Islands, some of the more southerly Outer Islands are close to the cyclone belt, and during these months they can experience extremely rough conditions on occasion.
A 4mm shorty wetsuit is the minimum protection recommended for the Outer Islands. Islands with big drop-offs and walls often have marked thermo-clines with temperatures ranging from 19 to 27ºC and a full suit is an advantage for most divers.
Dive Types & Depths
With 43 Inner Islands to choose from, variety is the order of the day. All of these northerly islands offer impressive granite reef locations where the sculptured rocks can be covered with soft corals and sponges, and fish life is prolific, due to the archipelago’s isolation and also strict conservation rules.
Wreck dives are available in some areas but only the islands to the south have wall dives, drop-off dives and drift diving opportunities as well.
Outer Island diving is rich and varied, featuring everything from mini-walls and canyons to migrating Manta Rays, numerous wreck sites and some of the finest Gorgonian fans in the Indian Ocean.
Diving on Aldabra’s terraced walls is dramatic and Green Turtles are common both in water and on their habitual pilgrimages up the beach to nest.
The Cosmoledo atoll offers huge hard coral bommies with 3 metre Gorgonian fans and massive barrel sponges all under the watchful guard of inquisitive Potato Bass.
Astove’s settlement reef presents another awe-inspiring wall dive whose reef top is incised with crevasses and caves and boasts a large resident Green Turtle population.
Dive depths vary, ranging from 8 to 20 metres for inshore sites and up to depths of 40 metres for dives offshore.
The Inner Islands’ marine life reveals an abundance of fish even on shallow inshore reefs and features different types of Butterfly fish and Angel fish, Soldier fish, Squirrel fish and Sweepers among many others. The island reefs are also havens for many invertebrates including Octopus, Spiny Lobster and a plethora of Nudibranchs, such as the Spanish Dancer.
Sites with regular current flows support fan corals and colorful tree coral formations while more remote sites shelter the larger fish species, such as the Napoleon Wrasse, Giant Grouper, Reef Sharks and Ribbon-tailed Stingrays. Most spectacular are the plankton-eating Whale Sharks found all year around the Inner Islands, with peak sightings in August, and October through January.
Marine life around the relatively isolated Outer Islands tends to be even more prolific, with frequent sightings of many of the larger grouper species, particularly the spotted Potato Bass as well as Grey Reef, Silver Tip, Nurse Sharks and the occasional Hammerhead Shark.