Kumai Reef is located some 40min from Semporna NE of the Gaya Island Group and only barely exposed during low tide. While the west side of the reef drops steeply down to approximately 40m the east side slopes very gently down to 30m before dropping another 10m to the sea floor. Coral growth is excellent on that side and common marine life encountered include eagle rays, blue spotted sting rays and whitetip sharks at the deep end. Nurse sharks and lobster can also be found under large table coral. At both the north end and the south end of the reef currents can be quite swift thus providing a good chance to spot schooling fish like banner fish, blue trigger fish and surgeon fish while manta rays sometimes pass overhead.