Trip report: 15th December 2024, 6 days in Surin and Similan National parks

Six Days and Five Unforgettable Nights: Diving the Similan and Surin Islands

The Andaman Sea is home to some of the most stunning underwater landscapes in Thailand, and our journey into its heart took us to the renowned Similan Islands and Surin National Park. With their vibrant marine ecosystems, dramatic rock formations and world-class dive sites, these destinations are a true diver’s paradise.

Our guests this week were an energetic mix of adventurers from Germany, France, the UK, Australia and Luxembourg. United by a shared passion for the ocean, we ventured into two Marine National Parks in the North Andaman, renowned for their vibrant marine life and spectacular underwater landscapes.

The Similan Islands, whose name fittingly means “nine” in Malay, form a cluster of breathtaking isles. Just to the north, Koh Bon and Koh Tachai serve as gateways to Surin National Park, adding even more wonder to the experience. Departing from Khao Lak, this voyage promised a tapestry of unforgettable sights above and below the surface.

Sunset over the Similan Islands — Sunset in the Similan Islands

Diving adventure in the Similan Islands — Diving the Similan Islands

Underwater scenery in the Similan Islands — Exploring the Similan Islands

Day 1: Similan National Park – Honeymoon Bay, West of Eden, Elephant Head and Turtle Rock

We started our adventure with a check dive at Honeymoon Bay on Island Number 4. The coral garden and pristine sandy bottom were teeming with marine life. Moray eels, lionfish, peacock groupers and an octopus made appearances, while Camille spotted a stunning comet longfin. Divers also encountered sealface pufferfish, gobies, butterflyfish and the graceful humpback unicornfish.

Our second dive took us to West of Eden on Island Number 7, where we marvelled at a vibrant coral garden bustling with life. Juvenile rockmover wrasse danced in the sand, while blue-spotted pufferfish peeked out from coral crevices. Angelfish, snappers, fusiliers, surgeonfish and tilefish were abundant, making this dive truly delightful.

For our third dive, we explored the iconic Elephant Head Rock, renowned for its massive boulders and swim-throughs. Highlights included a giant trevally, a blue-and-yellow ribbon eel and colourful nudibranchs adorning the rocks. Divers also spotted parrotfish, triggerfish and a playful school of bluefin trevally hunting glassfish.

The day concluded with a mesmerising night dive at Turtle Rock, near Donald Duck Bay. Shrimps and crabs were out in abundance: banded boxer shrimp, marble shrimp and Durban dancing shrimp stole the show. A giant moray eel stalking a snapper added an element of drama, while a tiger cowrie and an ornate spiny lobster rounded off our enchanting night.

Comet longfin Calloplesiops altivelis in the Similan Islands — Comet longfin – Calloplesiops altivelis

Day octopus while diving in Thailand — Day octopus

Sealface pufferfish while diving in Thailand — Sealface pufferfish

Tiger egg cowrie while diving in Thailand — Tiger egg cowrie

Day 2: Similan Islands

We began the morning at Xmas Point, where one group was delighted to discover a pair of baby harlequin shrimps munching on a sea star, while another group came across a white-tip shark swimming close by and a curious octopus. Parrotfish and titan triggerfish also came for a quick glance as we explored this dynamic dive site.

Our second dive took us to Three Trees, where we encountered a playful hawksbill turtle and observed garden eels swaying gently in the sand. The highlights of this dive included potato groupers and Moorish idols, as well as blue-spotted rays gliding elegantly through the water.

Next, we made our way to Koh Bon Bay, where we were greeted by a school of platax, or batfish. The spectacle was enhanced by the presence of lionfish, lobsters and peacock mantis shrimps, along with yellow fusiliers and bluefin trevally darting through the reef.

We concluded the day with a dive at Koh Bon, which featured Andaman sweetlips, tapestry shrimp and squat shrimps. An octopus made a memorable appearance, and we were particularly thrilled to spot the vibrant Halgerda tessellata nudibranch, which was truly a special treat.

Halgerda tessellata nudibranch in the Similan Islands — Halgerda tessellata

Colourful parrotfish while diving in Thailand — Parrotfish

Pair of young harlequin shrimps feeding on a sea star — Pair of young harlequin shrimp munching on a sea star

Hawksbill turtle in the Similan Islands — Hawksbill turtle

Day 3: Koh Bon and Koh Tachai

Some divers began their day at Koh Bon West Ridge, where Maldivian sponge snails, schools of fusiliers, triggerfish, batfish and anemonefish were abundant. While others explored the deeper Koh Bon Pinnacle, which was equally rich in marine life.

For the second dive, we ventured to Koh Bon North Ridge and North Reef, enjoying remarkable visibility and sunlight streaming through the water. Divers spotted banded sea snakes, barracudas, lionfish and baby fimbriated moray eels. Shrimp, including Durban dancers and boxing shrimp, added charm to the reef.

Dive three took us to Koh Tachai Pinnacle, where the light and visibility were breathtaking. Schools of fusiliers and snappers swarmed around the reef, while giant potato groupers and pufferfish lingered on the plateau. A school of batfish hovered near the walls, accompanied by octopuses and stunning sea fans.

The sunset dive at Koh Tachai Pinnacle featured no current and an abundance of marine life. Mackerel, giant trevally, dogtooth tuna and schools of fusiliers swirled around the site. Potato groupers and a small yellow boxfish provided a perfect ending to the day.

Titan triggerfish while diving in Thailand — Titan triggerfish

Abundant marine life in the Similan National Park — A fish-filled dive in the Similan National Park

Clownfish in their anemone at Koh Tachai Pinnacle — Clownfish in their anemone

Banded sea krait while diving in Thailand — Banded sea krait

Day 4: Surin National Park

School of red snappers in Surin National Park — Red snappers

The wind picked up as we made our way towards Surin National Park, prompting us to adjust our plans for safety. We began our adventure at Yellow Rock, located on the southern tip of South Surin Island. Although the visibility and current posed some challenges, our most determined divers were rewarded with sightings of a school of yellowtail barracuda, a massive school of yellow fusiliers, and a solitary humphead parrotfish.

Our second dive at Bungalow Rock, situated northwest of South Surin Island, offered calmer conditions and clearer waters. The underwater landscape was vibrant, featuring boulders teeming with life, including barracudas, sweetlips, shy potato groupers and a giant moray eel that made this dive truly memorable.

The final two dives of the day took us to the legendary Richelieu Rock. Although the visibility wasn’t perfect, the site delivered its usual enchantment. Schools of yellowtail barracuda, pickhandle barracuda, trevally, rainbow runners, fusiliers, and snappers painted a mesmerising underwater scene. The sight of cuttlefish laying eggs added to the excitement, while as the sun began to set, the waters came alive with activity as predators started their hunt.

After the sunset dive, we celebrated with a barbecue in the bay of the Surin Islands—a well-deserved feast for our hardworking divers.

School of barracudas at Richelieu Rock — School of barracudas

Bigeye trevally while diving in the Surin Islands — Bigeye trevally

Day 5: Richelieu Rock and Return to Koh Phayam and Ranong

The trip concluded with two final dives at Richelieu Rock, which once again showcased its incredible biodiversity. Schools of barracuda mingled with fusiliers and snappers, while longnose emperors prowled near the rock. Boxfish, trumpetfish and blue-spotted boxfish were just a few of the vibrant reef inhabitants we encountered. Porcelain crabs, peacock mantis shrimps and Durban dancing shrimps delighted macro enthusiasts.

With smiles on our faces and memories of breathtaking dives, we headed back towards Ranong, making a brief stop at Koh Phayam to drop off some guests. This journey was truly unforgettable.