Ko Haa’s scuba diving highlights include The Lagoon, The Cathedral and The Chimney. There are also underwater pinnacles, drop-offs, walls, bolders and other caverns, inter-connected chambers and swim-throughs to explore.
We make daily dive trips to Ko Haa every day on board our luxury dive boat MV Moskito.
Ko Haa, which means ‘Five Islands’ in Thai, has a central lagoon area that is ideal for beginner divers. It offers a safe and relaxed starting point for you to take your first underwater breaths and there are some extremely friendly little Porcupine Puffer Fish, ready to make your acquaintance in the large, sandy bay area. The bay slopes gently onto the reef allowing you to progress into your first dive effortlessly.
The marine life that can be found at Ko Haa varies from rare Ghost Pipefish measuring only a few centimetres, to an abundance of Octopus hiding amongst the rocks and crevices. A Hawksbill Turtle is often seen swimming amongst the pristine coral. Marble Rays, Eagle Rays, Whale Sharks and even Manta Rays are spotted here occasionally. You can’t predict exactly what you’ll see, but it’s always a pleasant and rewarding surprise!

The crystal-clear waters and consistent visibility of 25m+ make Ko Haa an un-forgettable scuba diving and snorkelling destination. We keep group sizes small to ensure you get the most out of each fun dive. This also reduces impact on our reefs. Our emphasis is on safety, fun and personal service within a relaxed and stress-free environment. You will find the atmosphere and service on our dive boats, beyond anything you have experienced before!
Our experienced Instructors and Divemasters know the dive sites extremely well, and are happy to discuss what you would like to see, and the type of dive or snorkel experience you would like to have. Each dive is personally planned with the divers in each group, to ensure you enjoy each and every dive you make with us.
A full briefing is provided at each site, with helpful tips on what to look for, safety information, and the most interesting places to visit.

The Lagoon
Crystal-clear waters, stunning visibility, pristine corals and great macro & juvenile marine life make the Lagoon an unforgettable dive destination.

The Cathedral
The Cathedral is a Ko Haa highlight not to be missed! The large interconnected chambers and swim throughs offer stunning silhouette photo opportunities.

The Chimney
The famous Chimney system has both a vertical and horizontal tunnel system that widens into open chambers with windows facing north and south.
The consistently good visibility makes Ko Haa ideal for all kinds of underwater photography and videography and is especially popular with macro enthusiasts.
Koh Haa Dive Site Tips – Insider Knowledge from the Locals!
Koh Haa’s central lagoon area is a must-see for anyone visiting Ko Lanta. The crystal-clear waters make for an underwater photographer’s paradise and the wealth of macro and juvenile marine life is sure to captivate even the most experienced divers. For beginners, the Lagoon offers a safe and relaxed starting point to take your first underwater breaths. Friendly Porcupine Pufferfish are ready to make your acquaintance and the gently sloping reef allows you to progress effortlessly into your first dives.
The caverns are one of Ko Haa’s highlights and consist of a series of large interconnected chambers and swim-throughs. The largest cavern has three chambers and is known as The Cathedral. The first two chambers are connected by a shallow swim through at about 9 meters, which offer stunning silhouette photo opportunities. At low-mid tide, it’s possible to surface inside the Cathedral and see the limestone stalactites looming from the high ceilings as the light cascades upwards from the wide entrance below.
Ko Haa Neung is home to the famous Chimney system, as well as the site for the annual Clownfish Release Project. The lower entrance can be found at 16m – a narrow crevice carved into the southern face that widens into a chamber large enough for 3-4 divers to gaze upwards, almost to the surface. A side-tunnel accesses a large, shallow chamber with huge windows facing north and south. You can find sea snakes, lionfish, nudibranches, glass shrimps and many other small crustaceans and cowries on this site.
Overview Map of the Dive Sites at Ko Haa