In Borneo most of the scuba diving locations are to be found in Sabah, northern Borneo. Sabah is home to a range of popular diving locations including the following:-
For World famous dive locations choose Sipadan or Layang Layang. Both offer diving along drop offs, sightings of pelagics and regularly feature in the top diving locations in the World.
Muck diving at Mabul - Mabul may not have the stunning reef diving offered by neighbouring Sipadan, but it is compensated by offering some really cool muck diving being home a wide variety of unusual critters including nudibranchs, mandarinfish, frogfish and lots more.
The most accessible diving is offered at Tunku Abdul Rahman Marine Park - the Marine Park is easy to visit from Kota Kinabalu and offers calm, sheltered coral reef dive sites suitable for beginners as well as offering chilled out diving for more experienced divers.
For idyllic island resort diving check out Lankayan Island or Pulau Mataking. Both have just one Resort located offering a secluded stay, white sand beaches and diving along the reefs fringing the island.
If you are into wreck diving then check out the wrecks located in the waters near Labuan - the American Wreck, Australian Wreck, Cement Wreck and the Blue Water Wreck. Dive Centre(s) in Brunei typically offer diving trips to the wrecks.