Koh Haa consists of five islands. The most well-known are Koh Haa Yai and Koh Haa Lek. They belong to the Mu Koh Lanta Marine National Park. Koh Haa Yai is the southernmost and largest island in the Koh Haa group. Visitors generally come to Koh Haa not for the beaches, but for diving. Many divers explore the three main caves southwest of Koh Haa Yai. Two of them are connected. The largest cave is often called the "Cathedral." It significantly contributes to the reputation of the dive site, which is considered one of the most beautiful in Thailand. The Cathedral is easily accessible through an opening 6 to 13 meters deep. Inside, divers can surface and enjoy a breathtaking view. Stalactites hang from the high ceilings, and the light filtering in from the water gives the Cathedral caves a magical atmosphere. Numerous marine species inhabit the waters around Koh Haa Yai: ghost pipefish, gorgonians, lobsters in rock crevices, lionfish, and with a bit of luck, you might even spot whale sharks. In April, whales pass by Koh Haa Yai on their annual migration.

Diving is generally possible in Koh Haa from October 15th to May 15th. During the rest of the year, it's the off-season, and the Mu Koh Lanta Marine National Park is closed to tourists to allow the ecosystem to recover. Dives in the dome are reserved for experienced divers and are not suitable for beginners.

Almost all diving agencies in Koh Lanta, Koh Phi Phi and even Phuket offer day trips to Koh Haa, including the famous dive in the underwater cathedral.

How to get there

How do you get to the Koh Haa islands for diving? Almost all diving agencies in Koh Lanta, Koh Phi Phi and even Phuket offer day trips to Koh Haa, including the famous dive in the underwater cathedral.