Dive Site: Secret Reef

About Secret Reef

Secret Reef, nestled adjacent to Hin Raab South, is a captivating dive site close to Koh Chang, forming a unified, diverse underwater ecosystem. It is celebrated for its unique coral canyons, where whip corals gently sway and flower and spiny cabbage corals thrive, creating a macro paradise. This site boasts a shallow plateau at 5-6 meters and a maximum depth of 12 meters, making it ideal for Open Water divers, try dives, and those seeking a tranquil, uncrowded experience. The underwater topography includes distinct canyons that guide divers across the reef. Marine life encounters are frequent, with colorful nudibranchs adorning surfaces, blue-spotted stingrays resting on the sand, and moray eels peeking from their shelters. Barracudas are also spotted patrolling the reef edges, adding to the site's rich biodiversity. Divers can explore historical remnants, including an ancient teapot and scattered gunship bullets, providing a glimpse into the area's past. Combining Secret Reef with Hin Raab South allows for extended bottom time, making it perfect for thorough exploration and underwater photography.

Dive site facts: Secret Reef

Depth

5–12 m

Current

Mild to none

Entry

Mooring line descent

Level

Open Water Diver, Try Dives

Dive type

Reef, macro, coral canyon

Region / port

Koh Chang, Eastern Gulf of Thailand

Coordinates

8.6886° N, 98.0460° E

Conditions & Currents

Secret Reef is generally known for its suitability for relaxed exploration, suggesting minimal to no significant currents. It offers conditions that are favorable for Open Water divers, implying that strong, challenging currents are not a predominant feature of the site. Calm conditions are expected, allowing for comfortable navigation through the coral canyons and over the shallow plateau. The site's nature permits extended bottom time, further indicating stable underwater environments without demanding current scenarios that would limit dive duration. Divers should still remain aware of any localized water movements typical of reef structures and consult with local dive guides regarding daily conditions.

Marine life & sighting chances

Nudibranchs

common

Blue-spotted stingrays

common

Moray eels

occasional

Barracudas

occasional

Whip corals

common

Flower corals

common

Spiny cabbage corals

common

Dive profile & how the dive runs

Begin your dive with a descent along the mooring line, targeting a depth of approximately 12 meters. From this point, navigate the distinct coral canyons that meander across the reef, providing a natural guided path. Along the route, explore the vibrant coral gardens and search for unique site features such as an ancient teapot and scattered gunship bullets. The dive includes exploring a shallow plateau found at 5-6 meters, which is ideal for extending bottom time and allows for a gradual ascent. Conclude the dive by returning to the mooring line, where the safety stop is performed, ensuring a smooth and controlled ascent.

Underwater photography

Secret Reef is particularly rewarding for macro photography, given the abundance of colorful nudibranchs that dot the reef. A macro lens will allow you to capture intricate details of these tiny creatures, as well as the moray eels peeking from crevices and the vibrant coral polyps. For wider shots of the coral canyons and blue-spotted stingrays on the sandy bottom, a wide-angle or standard lens can be effective. Consider using a strobe or video lights to bring out the true colors of the corals and marine life, especially in deeper sections or within the canyons. Practice excellent buoyancy control to avoid disturbing delicate corals and to get close enough to small subjects without stirring up sediment.

Combine with nearby dive sites

• Hin Raab South

  Connected and often combined with Secret Reef for extended exploration.

• HTMS Sattakut Wreck

  The HTMS Sattakut Wreck is a 48-meter long, decommissioned U.S.

• King Cruiser Wreck

  The King Cruiser Wreck, a former 85-meter car and passenger ferry, transformed into one of Thailand's most celebrated artificial reefs…

• Shark Point

  Shark Point is an exceptional dive site located within the highly protected Jardines de la Reina Marine Park off Cuba's southern coast.

• Koh Dok Mai

  Koh Dok Mai, meaning 'Flower Island,' is a distinctive limestone outcrop located in Thailand's Andaman Sea, between Phuket and Phi Phi…

Getting there & logistics

Access to Secret Reef is typically arranged through dive centers operating from Koh Chang, a popular island in the Eastern Gulf of Thailand. Koh Chang itself is part of the Mu Koh Chang National Marine Park, which is a prime diving region in the area. Divers usually fly into Bangkok's Suvarnabhumi International Airport (BKK), which serves as the main gateway to the country. From Bangkok, domestic travel options to Koh Chang are available, though specifics like flight duration or ferry connections are not detailed for this specific site. Day trips are common, as Secret Reef can be explored in combination with its adjacent site, Hin Raab South, allowing for a comprehensive two-dive day. Permit and park fees for the national marine park are generally required.

Safety & environment

While Secret Reef is considered suitable for Open Water divers, general dive safety protocols apply. Divers should ensure they have adequate insurance covering dive accidents and potential evacuation, as recompression chambers in Thailand are primarily located in major hubs like Phuket and Pattaya, implying a potentially distant evacuation in emergencies from Koh Chang. Site-specific hazards are minimal, given the shallow depths and generally mild currents, but divers should still maintain awareness of their surroundings within coral canyons. Adherence to a maximum depth of 12 meters is crucial. Always dive with a certified guide and follow their specific briefing regarding current conditions and site navigation. Good buoyancy control is essential to protect the delicate coral formations and avoid disturbing marine life or kicking up sediment.

Who it suits — and who it doesn't

FAQ

Secret Reef FAQ

Liveaboards diving Secret Reef

These liveaboards may visit Secret Reef 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