Boulder Island is rich and diverse in life.

Boulder Island hosts a high biodiversity of life that guests and marine biologists have enjoyed to explore and uncover since the resorts opening. In addition to research, regular reef cleaning and marine conservation projects are underway to protect this underwater paradise.

Marine research documents


Boulder Islands coral reefs consist of a large variety of soft and hard coral species including Ctnella chagius and a range of Acropora corals. Montipora tuberculosa has been observed as comprising over 50% of the coral reef in Moken Bay. Heliopora coerulea identified by the IUCN (International) as a vulnerable species exists in abundance around Boulder Island making a strong case for the protection of this marine area.


Numerous, large fields of anemones have been observed throughout the surrounding waters of the island. Anemones provide a good indication of water quality around the island. Due to their distribution in both shallow and deeper waters of the reef, snorkelers and divers can enjoy observing their symbiotic relationship with an array of anemone fish species, including the popular clown fish.


Fish biodiversity surrounding Boulder Island is ever-growing as we continue to encounter new species regularly by both guests and researchers. Some of our favourite species often sighted include: Oriental sweetlips, surgeonfish, blacktip reef sharks, barracuda, ribbon eels, pipefish and various species of stingray.


Sea stars, brittle stars, sea cucumbers and sea urchins are scattered throughout our bays and deeper waters.


Nudibranchs are prolific across the coral reefs. They can be extremely beautiful due to their striking patterns and colour which is a defense mechanism to avoid being eaten by reminding potential predators of their toxicity. These are extremely desirable for most underwater photographers and there are plenty of species being discovered to be inhabiting our reefs almost daily.


There are variety of birds present on the island. The Nicobar Pigeon was observed. It is currently listed as “near threatened”. Imperial Pigeon, White-Rumped Shama, Bhamany Kite, White-Bellied Sea Eagle and the Pacific Reef Egret appeared to be the predominate marine birds in the island.



Reptiles can be found both in the jungle and the water. These include the occasional encounter with the beautiful reticulated python and tree snake, as well as the monitor lizard, which is the second largest lizard in the world! Sea snakes can be found traversing on top of the reef and are a spectacle to watch due to their amazing black and white banded pattern making them very distinct. Inhabiting the house reef are several hawksbill turtles, that you can see resting underneath rocks and coral as well as foraging for food, they are simply magical to observe.