Koh Haa (5 islands in Thai) is a group of five small islands just 25km west of Koh Lanta. The islands are dived by daytrip from Koh Lanta and Phi Phi or by liveaboard boat from Phuket. Liveaboards from Phuket normally dive Hin Daeng, Hin Muang and Phi Phi as well as Koh Haa. There is deep water seperating the islands. Currents can be strong in areas but it's always possible to find a sheltered area. Visibility is average, around 5m to 20m. Maximum depth is 30m. There are several mooring buoys.

The main attraction of diving Koh Haa is "the Cathedral" of Koh Haa Yai. The Cathedral is a large underwater chamber with two entrances and lots of natural light inside making it save to dive in. Inside the chamber you can surface to look up at the amazing stalactite formations hanging down from the ceiling above. There are other inter-connected swim-throughs in the same area. There are also smaller cave entrances leading off from the main chamber which should only be dived by divers trained in diving in overhead environments.

Koh Haa does not have regular big fish sightings although whale sharks, manta rays and eagle rays are spotted here on occasion. More common are leopard sharks and Hawksbill turtles are also seen. Look for octopus in the rocks plus moray eels. Dog faced pufferfish are numerous as are porcupine fish. Lionfish and scorpionfish will also be seen. Macro photographers should keep an eye out for harlequin ghost pipefish and seahorse.

Several shallow sandy patches make Koh Haa a good place to do some dive training, maybe an advanced course as part of your liveaboard? Some operators can arrange cavern diver training as well.