Salomon Islands Atoll

The Salomon Islands Atoll is unusual within the Chagos Archipelago because it forms a true double atoll, two separate horseshoe-shaped reef structures separated by a shallow sandy bank that is periodically submerged during high spring tides, creating a dynamic and visually distinctive landscape that changes character with the tidal cycle.

The two principal islands are each covered in dense coconut plantation, a legacy of the 19th-century coconut-oil trade that drove settlement across the Chagos Archipelago, and the palms provide canopy for low shrub and the scattered remains of the stone structures that once housed plantation workers and their families.

The surrounding reef flat is broad and exposed at low tide, revealing a terrain of coral rubble, tide pools and isolated bommies that supports a wide variety of intertidal species including hermit crabs, small reef fish and occasional green turtles hauled out on the reef flat to rest.

Like the rest of the Chagos Archipelago, the Salomon Islands have been uninhabited since the mid-20th century, and the former plantation buildings have been largely reclaimed by vegetation, leaving a landscape that is peaceful and overgrown rather than desolate.

The atoll sits within the larger 2010 marine protected area that covers the entire Chagos Archipelago, and the waters surrounding it are characterised by clear visibility, strong tidal currents through the reef passages and the kind of coral diversity that makes the Chagos reefs a reference site for the Indian Ocean.

The Salomon Islands were used historically as a stopover by sailing vessels navigating between the African coast and the Far East, with the islands providing fresh water from shallow wells and the lagoon providing shelter from the open ocean swell that can build dramatically across the fetch of the central Indian Ocean.

The double-atoll structure means that the inner sandy bank connecting the two reef systems is exposed at low tide and submerged at high tide, a rhythm that creates distinct ecological zones: intertidal flats with their own characteristic species, and subtidal areas where coral growth is concentrated around the edges of the channels.

The seabird nesting colonies on the Salomon Islands are particularly impressive during the breeding season, when the coconut canopy is alive with the calls of sooty terns and the air above the islands is thick with birds moving between the nesting trees and their feeding grounds on the surrounding ocean.

The tidal flooding of the connecting bank creates a distinctive ecological gradient, with marine organisms adapted to both subtidal and intertidal conditions found in close proximity, making the Salomon Islands a small-scale natural laboratory for studying how marine life adapts to the twice-daily cycle of immersion and exposure.

The Salomon Islands are one of the very few double atolls in the world; the tidal dynamics and ecological character of the connecting bank offer a combination of marine habitats found in few other places.

The overgrown 19th-century coconut plantation landscape gives a tangible sense of the human history of the Chagos Archipelago, a layer of activity that has otherwise been almost completely erased from the islands.

The surrounding reefs, protected by the 2010 marine protected area, offer high-quality diving and snorkelling with significant fish biomass and coral cover that is rarely encountered in the wider Indian Ocean.