'Hin Daeng & Southern Islands' is often the term used by dive centres when referring to several of diving areas located to the south and east of Phuket. Hin Daeng is the best dive site in this region, but the others are always very nice. Most of the following locations are visited on a ‘Southern Islands’ liveaboard cruise.
Anyone talking about diving at 'Hin Daeng' is actually referring to twin dive sites, Hin Daeng & Hin Muang. These names mean ‘Red Rock’ & ‘Purple Rock’ in Thai, and they are excellent dive sites. They are underwater seamounts, with the peak of only Hin Daeng breaking the water’s surface at low tide. Due to their exposed location, Hin Daeng & Hin Muang are not suitable for snorkellers, and waves can sometimes be an issue. They are only suitable for certified scuba divers, and some would say that a minimum of 30 logged dives and/or Advanced certification level is necessary to enjoy them properly. the two pinnacles are surrounded by deep water in every direction, which means that there's plenty of resident marine life and pelagic species also visit every day.
Koh Haa is a small group of five uninhabited islands which are visited by liveaboard boats from Phuket and by day-trip diving boats from Koh Lanta. There is excellent diving here for all levels of certification and experience, as well as a couple of beaches and some excellent snorkelling. The limestone cliffs above the surface, and swimthroughs, caverns and marine life below it make this an incredibly-beautiful place to visit. the most-popular dive sites are 'the Cathedral' and 'The Chimney.' The Cathedral has a sort-of cave with a huge opening. But The Chimney is a challenging dive site where you really need to focus on getting through without panicking or wasting air. However, once inside you will feel that it was well worth the effort. Koh Haa has a few other dive sites, including The Lagoon and others.
Koh Phi Phi and Phuket need very little introduction to most people who come to Thailand to scuba dive. They are both extremely popular with tourists for nightlife, and other outdoor activities. Most of Phuket’s and Phi Phi’s dive sites are easy enough for all to explore but exciting enough for experienced and even professional divers to enjoy.
Phi Phi has a new wreck, and the famous Bida Islets on the southern tip. Most of the better Phuket dive sites are actually located between Phuket and Phi Phi. These are King Cruiser Wreck, Shark Point, Anemone Reef and Koh Doc Mai. There are also the Racha (Raya) Islands, which can be dived all year round and sometimes offer some pelagic surprises.