THE CHAGOS ARCHIPELAGO - Dive Atlas Of The World: An Illustrated Reference To The Best Sites - Jack Jackson

Dive Atlas Of The World: An Illustrated Reference To The Best Sites - Jack Jackson (2016)


by R Charles Anderson

CHAGOS, AN ISOLATED GROUP OF ATOLLS and reefs, lies 480km (300 miles) south of the Maldives in the central Indian Ocean. This is one of the world’s least accessible places.

The archipelago consists of five atolls and 10 reefs and submerged shoals. There are about 50 islands, which in general appearance are similar to those of the Maldives. There is a US military base on the southernmost atoll, Diego Garcia. The other islands are uninhabited. Because of the military presence, the whole archipelago is off limits to visitors.

The French and the British laid rival claim to the islands in the 18th century, with the French establishing coconut plantations on several of the islands. However, the capture of Mauritius (from where the French had administered the Chagos) in 1810, left the islands firmly in British control, a position that was ratified by the Treaty of Paris in 1814. The Chagos has remained a British possession to this day, and is now known officially as the British Indian Ocean Territory.

In 1966 a 50-year agreement was signed between the UK and the USA, granting the USA use of the islands for defence purposes. Under this agreement the coconut plantations were closed and the workers forcibly deported to Mauritius in 1970. In December 2000, after an appeal to the High Court in London, the displaced islanders, or ilois, won the right to return to the Chagos.

The British government is currently investigating the feasibility of re-establishing settlements in the Chagos; and options for viable commercial activities. One possibility is diving tourism. Until that happens, commercial dive charters remain banned. To dive in the Chagos you will have to join an authorized scientific expedition, or travel there by private yacht. Divers who do manage to find their way to the Chagos will find the diving very similar to that in the Maldives. However, there are a few fascinating differences. For one, the Maldives lacks the submerged ‘offshore’ reefs that are so common in the Chagos. Also, the Chagos is home to a few marine animals found nowhere else in the world, for example the Chagos Anemonefish, (Amphiprion chagosensis).

As with the Maldives, the entire Chagos is one enormous dive site. To choose just a handful of spots is almost impossible, so I have tried to pick a variety of different dive types, from each of the three main atolls. While it is possible to dive from the beach of some islands, you really need a boat to get around the atolls and to make these dives.


Salomon is a small atoll, only 8km (5 miles) long, but it is almost entirely enclosed. As a result it offers particularly safe anchorage and is the favourite of visiting yachtsmen. The single entrance channel on the northern side is wide, but shallow - only 6-8m (20-25ft) deep. This channel offers some great diving. A flood tide brings clear water from outside, and a modicum of safety too, since the current will carry you into the atoll and not out into the ocean if you miss your boat cover. At the outer edge of the channel, the reef drops away steeply to great depths. Near the edge are superb Acropora table corals, which further down the slope are replaced by beautiful sea fans. Look out here for the Chagos Anemone-fish, which prefer reef slopes to shallower reef flats. This is also a likely place for sharks.


This small sheltered reef lies on the inside of Île Mapou, inside the northwestern corner of Peros Banhos Atoll. Here a calm shallow embayment, no more than 8m (26ft) deep, offers extended bottom times among rich corals interspersed with white sandy patches. This is ideal territory for the macro photographer hunting obscure wrasse and gobies, and also for searching out nudibranchs and flatworms. This is a particularly good site to visit for a second dive, after a deep dive on the outer reef, or if conditions are too rough on the outside.


In the southwestern corner of Peros Banhos Atoll is Île Vache Marine. On the northern side of this small island is a superb dive site, called Vienna Rock. It could be dived from the beach, but a small boat makes access much easier. Vienna Rock is a coral rock pinnacle reaching up from about 15m (50ft) to 8m 25ft) and it is plastered with marine life. Thick growths of gorgonias sprout from the walls, and in their shade a rich carpet of sponges and ascidians provides a rich hunting ground for the macro photographer. Further out, the sandy bottom slopes slowly down, providing a home for many other fascinating creatures.


The Great Chagos Bank is a vast maze of submerged coral reefs. The Three Brothers is a group of four (yes, four) small islands on the western side of the bank. Because the atoll rim of the Great Chagos Bank is not complete, big ocean swells crash in on the Three Brothers from all sides, even on calm days. Depending on conditions at the time, there may not be a sheltered side on which to anchor. One possible anchorage is on the extreme southeastern side of the reef of Middle Brother. This will put you right next to a rich coral wall and over a flat sand and coral reef step in 18m (60ft). Getting in could not be simpler - jump straight off the boat into a coral-lined swimming pool with more than 30m (100ft) visibility. There are great stony corals, including a dense patch of Heliopora corals on the main reef slope, as well as some unusual sponges. Several different species of parrotfish, numerous jacks, emperors and goatfish, and many others can be seen.



A diver takes a closer look at the north side of the Vienna Rock, in Peros Banhos Atoll. This side is festooned with Gorgonian Sea Fans.


Île aux Bénitiers offers good snorkelling in the translucent waters of the coral lagoon that encapsulate the Le Morne coastline.


The Mahébourg coastline offers the romance of a tropical island basking in a giant basin of warm turquoise waters, where divers can also try other forms of watersport.