At the northern tip of Temburong District lies this 25-sq-km mangrove-forested island reachable only by boat (45 minutes from BSB). Intrepid Tours runs half-day guided trips for around B$100 per person. Two kilometres of elevated walkways lead through the mangroves, which are the untamed habitat of proboscis monkeys and flying lemurs – if you're lucky you might spot one gliding down from the trees. Pulau Selirong is also known as Mosquito Island; bring repellent.
At certain times the tide levels are such that it is not possible to access the island.
