Mabul Island is reputed to be one of the best places for underwater macro-photography in the world. Located in the clear waters of the Celebes Sea off the mainland of Sabah, it is surrounded by gentle sloping reefs two to 40m deep. Covering some 21 ha., it is considerably larger than the nearby Sipadan Island and is home to the Bajau Laut tribe, one of many ethnic groups in Sabah. Diving is the main activity on this island, and it can be done all year round. Marine life that can be seen here includes sea horses, exotic starfish, fire gobies, crocodile fish, pipefish and snake eels. There are over eight dive spots.
There's no airport in Semporna, so book your flight to Tawau (some airlines via Kuala Lumpur/Kota Kinabalu) instead and a 45 minutes ride by taxi to Semporna.
For domestic, Airasia flies directly from LCCT (Kuala Lumpur) to Tawau, whereas Malaysian Airlines (MAS) at this moment only flies to Tawau via Kota Kinabalu. To reach Mabul Island, it is a 30-minutes boat ride from Semporna and 20 minutes from Sipadan Island.