Dive Site: Koh Haa — Lagoon

About Koh Haa — Lagoon

Koh Haa Lagoon is a picturesque and protected dive site formed by islands #2, #3, and #4 of the Koh Haa archipelago, approximately 1.45 hours by boat from Koh Lanta. This stunning turquoise lagoon is renowned for its tranquil, crystal-clear waters and white sandy bottom, making it an ideal location for divers of all experience levels, from beginners practicing skills to advanced divers exploring its varied topography. The lagoon itself is relatively shallow, ranging from 5 to 15 meters, featuring scattered hard coral bommies that host large giant morays, curious porcupinefish, and camouflaged sea moths. Beyond the sheltered lagoon, the surrounding islands present more diverse environments. Koh Haa #3 boasts a white sand beach beneath vegetation-covered cliffs, while islands #2 and #4 are primarily limestone pillars. Divers can navigate around these smaller islands, where depths can reach 30 meters, revealing garden eels, swirling schools of yellow snapper, and glassfish-blanketed walls. A sandy slope between the islands is often patrolled by juvenile barracuda, and hawksbill turtles are regular visitors, feeding on bubble coral. The site is characterized by vibrant soft corals, sea fans, and plate corals, especially on the west side of Koh Haa #3. These structures provide excellent habitats for an array of macro life, including ornate ghost pipefish, frogfish, mantis shrimp, and harlequin shrimp. Lionfish and clownfish are also commonly observed throughout the area. The combination of shallow, sheltered areas and deeper, reef-rich sections ensures a rich and rewarding dive experience for everyone, from snorkelers to experienced photographers. The waters around Koh Haa Lagoon maintain excellent visibility, often ranging from 20 to 30 meters during the high season, and generally experience mild to moderate currents. Its location within Mu Ko Lanta National Park means a protected environment and less boat traffic compared to other popular sites, contributing to its

Dive site facts: Koh Haa — Lagoon

Depth

3–30 m

Typical dive

5–30 m, 50–60 min

Current

Mild to moderate

Visibility

5–30 m

Water temperature

27–30 °C

Entry

Boat / Giant stride

Level

All levels

Dive type

Reef, wall, macro, training

Night dive

Possible

Region / port

Mu Ko Lanta National Park

Coordinates

7.315, 98.978

Conditions & Currents

Koh Haa Lagoon typically experiences mild to moderate currents, which are generally manageable for all diver levels. Inside the main lagoon, currents are consistently calm, making it a perfect spot for training and beginner dives. However, outside the bay and between the limestone islands, currents can pick up, especially from north to south and vice versa. Dive operators use tide tables to plan dives accordingly, often mooring boats within the protected lagoon. Visibility is reliably good, averaging 15-25 meters, and can extend to 30 meters during the high season, attributed to less boat traffic compared to other popular sites. Entry is usually a giant stride from the moored boat into the calm waters of the lagoon, with planned routes often returning to the boat for easy exit.

Marine life & sighting chances

Giant Moray

common

Porcupinefish

common

Sea Moth

occasional

Flounder

occasional

Walkman (Stargazer)

rare

Garden Eel

common

Yellow Snapper

common

Juvenile Barracuda

occasional

Hawksbill Turtle

common

Ornate Ghost Pipefish

occasional

Frogfish

occasional

Mantis Shrimp

occasional

Harlequin Shrimp

occasional

Clownfish

common

Dive profile & how the dive runs

Diving at Koh Haa Lagoon typically begins with a giant stride entry from the boat into the calm, shallow waters of the lagoon, which averages 5-6 meters in depth. You can start by exploring the sandy bottom dotted with hard coral bommies, keeping an eye out for giant morays, porcupinefish, and sea moths. From the central lagoon, you can navigate towards the limestone pillars of Koh Haa #2 and #4. The depths around these islands gradually increase to over 30 meters, where you'll find gardens of eels and schools of yellow snapper. A sandy slope connecting the two islands is a good spot for juvenile barracuda. The west side of Koh Haa #3 offers a gentle slope to 18 meters, transitioning into walls adorned with soft corals, where hawksbill turtles often feed. The dive usually concludes with a safety stop within the sheltered lagoon before ascending back to the boat.

Underwater photography

Koh Haa Lagoon is an excellent location for both macro and wide-angle underwater photography due to its diverse topography and marine life. For wide-angle shots, consider capturing the dramatic limestone formations and the vibrant soft coral walls, especially on the deeper sections of Koh Haa #2 and #4. The interplay of light in the clear, shallow lagoon also creates compelling wide-angle opportunities. For macro enthusiasts, the bommies and crevices within the lagoon and along the walls are teeming with subjects like ornate ghost pipefish, frogfish, harlequin shrimp, and various nudibranchs. A macro lens (e.g., 60mm or 100mm) is highly recommended. Good buoyancy control is essential to avoid disturbing the sandy bottom and delicate corals, particularly when focusing on macro subjects. Bring a focus light to help your camera find tiny critters in hidden spots, and use strobes to bring out the true colors of the corals and marine life.

Combine with nearby dive sites

• Koh Haa — The Chimney

  A vertical swim-through with caverns and abundant marine life.

• Hin Daeng

  Famous for pelagics like manta rays and whale sharks, deep walls, and vibrant soft corals.

• Hin Muang

  Thailand's longest reef, known for purple corals and schooling fish.

• Koh Phi Phi — Bida Nai

  Limestone pinnacles with swim-throughs and a variety of reef fish.

• Shark Point

  A series of pinnacles known for leopard sharks and colorful anemones.

Getting there & logistics

Access to Koh Haa Lagoon is typically from Koh Lanta, which is reachable via Krabi International Airport (KBV) or Phuket International Airport (HKT). From these airports, you would take a combination of taxi and ferry/minivan to Koh Lanta. Dive trips usually depart from Saladan on Koh Lanta, with boat journeys lasting approximately 1 hour 45 minutes by slow boat or 45-60 minutes by speedboat. Most operators offer full-day trips, including 2-3 dives, breakfast, and lunch onboard. Koh Haa is part of Mu Ko Lanta National Park, requiring a marine park fee payable locally. The site is often combined with other Koh Haa dive sites in an itinerary, providing a diverse day of diving. Note that the marine park closes from May 16th to October 31st each year.

Safety & environment

The nearest recompression chamber is located in Phuket, approximately a 3-4 hour journey by speedboat and road, highlighting the importance of cautious diving. Emergency evacuation would involve initial stabilization on the dive boat, followed by transfer to Koh Lanta for further medical assessment and then transport to Phuket if required. Comprehensive dive insurance, covering medical emergencies and evacuation, is highly recommended. Within the lagoon, currents are generally mild, but outside the protected area, they can become moderate; divers should always follow their guide's instructions. Maintaining excellent buoyancy control is crucial, especially in areas with delicate corals, to prevent accidental damage. Always dive within your certified limits and conduct thorough buddy checks before each dive.

Who it suits — and who it doesn't

FAQ

Koh Haa — Lagoon FAQ

Liveaboards diving Koh Haa — Lagoon

These liveaboards may visit Koh Haa — Lagoon on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Mandarin Queen 9

Thailand

26 guests37.5 m

Manta Queen 8

Thailand

24 guests

$127/day

The Junk

Thailand

18 guests33 m

$163/day

Deep Andaman Queen

Thailand

23 guests30.5 m

$194/day

Explorer

Thailand

16 guests25 m

$150/day

Andaman

Thailand

20 guests26 m

$108/day

Stingray

Thailand

8 guests24 m

$245/day

Seatopia

Thailand

24 guests24 m