Dive sites in Thailand

Hin Bida is a submerged pinnacle system located southeast of the Phi Phi islands in the Andaman Sea. The topography consists of low-lying limestone boulders surrounded by extensive fields of staghorn and table corals that slope gently into surrounding sand plains. The site is widely recognized for frequent resting leopard sharks along the outer perimeter channels.

Hin Muang is a completely submerged oceanic pinnacle located south of Koh Lanta in the Andaman Sea. Named Purple Rock for the dense blankets of soft purple corals encrusting its sheer vertical drop-offs, the site plunges into deep open water. Strong currents frequently sweep the formation, attracting pelagic filter feeders alongside schools of predatory fish.

Located off the rocky southern headland of Kata Beach on Phuket's west coast, this shallow coastal reef features granite boulders sloping down to a sandy seabed with scattered hard coral bommies. It is one of the island's most accessible shore dives, popular for training dives, relaxed critter hunting, and night diving when nocturnal marine species emerge from the sand and reef crevices.

Rising out of the Andaman Sea south of Phi Phi Ley, the twin limestone islets of Koh Bida Nok and Koh Bida Nai form one of the premier marine habitats in the region. Underwater, dramatic vertical limestone walls drop into sloping reefs covered in soft corals and gorgonian fans, complemented by shallow hard coral gardens and swim-throughs. Divers frequently encounter schooling pelagics around the exposed points alongside reef sharks cruising along the sandy fringes.

Located north of the main Similan archipelago, Koh Bon stands out as a stark limestone islet rather than the granite boulders found on its southern neighbors. Divers descend primarily onto the dramatic western ridge, a submerged finger of rock that drops away into deep blue water and acts as an active cleaning station for pelagics. Plankton-rich currents sweep across the wall, supporting yellow soft corals, sea fans, and abundant schooling fish.

Koh Bon sits north of the main Similan chain, characterized by perforated limestone cliffs and a submerged western ridge that drops off into open water. Ocean currents sweeping past the point concentrate plankton, making it one of the premier cleaning stations in Thailand for pelagic visitors.

Rising vertically out of the Andaman Sea between Phuket and the Phi Phi Islands, Koh Doc Mai is a limestone monolith famed for wall and macro diving. The eastern flank features sheer drop-offs covered in dense clusters of yellow tube corals and expansive gorgonian sea fans, alongside two cavern openings that can be explored near the base. Divers drift along the dramatic rock face, peering into crevices where critters shelter from passing tidal currents.

Koh Haa forms a cluster of five limestone islets in the Andaman Sea, renowned for dramatic underwater topography including swim-throughs, caverns, and healthy hard coral gardens. The central lagoon offers calm conditions surrounded by shallow reefs, while outer walls descend into deeper water. Famous features like The Cathedral allow divers to explore interconnected chambers where ambient sunlight filters down from the surface.

Koh Haa forms a cluster of five limestone islets rising sharply from the Andaman Sea within the Mu Koh Lanta National Marine Park. Underwater, the karst topography plunges into vertical walls, vast sandy basins, and an extensive system of caverns and swim-throughs. The central lagoon offers shallow coral fields sheltered from open ocean swell, while the outer pinnacles drop toward deeper water where pelagics cruise past.

Koh Sii is a limestone islet located among the Ao Nang local islands off Krabi. Underwater, the steep karst walls plunge into a seabed dotted with massive boulders, forming narrow swim-throughs and sheltered overhangs. Large sea fans and patches of soft coral cling to the rock faces, while sandy gullies between the formations host benthic critters.

Submerged granite domes rise off the southern tip of Koh Tachai, forming a dynamic offshore plateau subject to energetic currents. Divers descend along mooring lines to granite boulders blanketed with sea fans, feather stars, and fields of hard corals. The open-ocean location draws pelagic species that patrol the perimeter while dense schools of trevally hunt along the reef crest.

Located among the Krabi local islands offshore from Ao Nang, Koh Yawasam features limestone rock formations sloping into a gentle sandy bottom with scattered coral heads. Divers frequently encounter leopard sharks resting on the sand, while crevices across the reef provide shelter for macro creatures and schooling reef fish. The shallow, sheltered profile makes it a regular stop for local day boats and training dives.

Richelieu Rock is an isolated limestone pinnacle rising from a sandy seabed in the Andaman Sea, just south of the border with Myanmar. Its horseshoe-shaped formation features steep walls, crevices, and ledges carpeted in vivid purple soft corals and sea anemones. Because it sits far offshore without shelter, open-ocean currents sweep past the rock, drawing massive schools of pelagic predators alongside rare macro critters sheltered in the crevices.

Located off the coast of Sattahip in the upper Gulf of Thailand, Samaesan offers an energetic mix of historical shipwrecks and rocky island reefs. The area is famous for the Hardeep, a sunken World War II cargo vessel covered in soft corals and sponges. Diver traffic here often contends with notable tidal flow moving between the offshore islands, creating nutrient-rich feeding grounds across the granite boulders and sloping sand bottoms.

Located off Koh Lipe in the Tarutao National Marine Park, Stonehenge consists of a cluster of towering granite pinnacles that rise from a sandy seabed. The massive rock formations are carpeted in soft purple, pink, and white dendronephthya corals that open fully when tidal currents sweep past. Schools of pelagic fish circle the pinnacle summits while macro critters seek shelter in the deep crevices.

Located along the eastern coast of Koh Bangu in the Similan Islands, Three Trees takes its name from a distinctive trio of trees visible on the shoreline above. The underwater terrain transitions gently from a shallow hard coral garden into a sandy slope dotted with massive granite boulders, sea fans, and soft coral colonies. Divers usually drift lazily southward along the reef profile while inspecting the sandy bottom for resting rays and garden eel colonies.