Rock Islands Southern Lagoon

The Rock Islands of Palau rise from a turquoise lagoon as hundreds of rounded green domes, each one a lump of ancient coral limestone capped with dense forest. Many are shaped like mushrooms or umbrellas, pinched in at the waterline where a notch has been worn into the rock. That undercut is the work of the sea and of grazing animals: sponges, bivalves, chitons, snails and sea urchins rasp away at the algae-covered limestone at tide level, slowly narrowing each island's base. Sources count between 250 and 300 islands, together covering about 42 square kilometres, the highest reaching 207 metres.

The islands lie in Palau's Southern Lagoon between Koror and Peleliu, and almost all are uninhabited. Hidden inside some of them are marine lakes, around 70 in all, bodies of seawater cut off from the lagoon except through fissures and tunnels in the old reef rock. The best known, Jellyfish Lake on Eil Malk, is home to millions of golden jellyfish that migrate across the lake every day; isolated for thousands of years, they have diverged from their relatives in the open lagoon. Several of the lakes are permanently layered, with oxygen-rich water at the top and a lifeless anoxic layer below, a condition rare among marine lakes anywhere.

Around the islands the reefs, channels and walls make this one of the most varied diving areas in the Pacific, with sites such as Blue Corner, the Blue Holes and German Channel, as well as wrecks from the Second World War, including the Japanese tanker Iro. On land, a bird area of nearly 4,900 hectares shelters most of Palau's endemic species, among them the Micronesian megapode, the Palau ground dove and the Palau fantail. In 2012 the Rock Islands Southern Lagoon, a protected area of some 100,200 hectares, was inscribed by UNESCO as a mixed World Heritage Site, recognised for both its natural and its cultural values.

Getting there

The islands begin just south of Koror, Palau's largest town, from which boats head out into the lagoon. The nearest airport is Roman Tmetuchl International Airport (ROR) on Babeldaob, about 25 km away and linked to Koror by bridge. The national capital, Ngerulmud, is some 40 km to the north.