Derawan is a turtle-breeding haven. So at night you can watch huge 300lb green turtles laying their eggs on the beaches and by day dive with dozens of these fabulous creatures on the house reef. They are totally approachable and unafraid of divers.
The island has its own turtle hatchery where the islanders nuture the young before their release into the sea.
We were allowed to help build a nest and also released a few of the youngsters one moonlit evening.
Meanwhile ornamental reef fish hang out in record density and diversity - fish and invertebrate species new to science are still being discovered on a regular basis here.
The shallow waters beneath the 200-metre jetty (which houses the resort's restaurant and bar) is home to some of the most bizarre-looking critters you will ever encounter. It's one of the best night dives in the world: you can encounter dumpling squid, crocodile fish, squat lobsters, decorator crabs, seahorses and dwarf scorpionfish in just two metres of water!
Nearby Sangalaki is known as the manta capital of the world. You often find up to ten of these massive, docile plankton-feeders curiously eyeing you while diving or snorkelling. The reefs here are shallow - maximum depth of around 20 metres - but they are rich in pristine hard and soft corals, more turtles and huge clouds of reef fish, while leopard sharks and whitetips are often spotted in the sandy corridors between the reefs.
Our dive guide supplied us with fresh coconuts straight from the tree after lunch on a deserted island.
Located off the North East coast of Borneo in the Celebes Sea, the small island of Derawan was until recently little-dived, living in the shadow of its more famous nearby cousin Sipadan. But overcrowding there led divers to discover this new treasure and its outlying, similarly unspoilt islands Sangalaki, Kakaban and Maratua - all within an hour of Derawan by speedboat.