Trip Report: South & North Andaman — 19th to 26th November 2025

Our new diving season began with a wonderfully international group joining us at Chok Thaeworn Pier in Phuket. Divers arrived from Switzerland, France, Holland, Belgium, Taiwan, Australia, Saudi Arabia, and Canada — including our special guest and paparazza Katie, already armed with her camera. With everyone settled in aboard the MV Smiling Seahorse, we started our southbound journey toward the crystalline waters of the Koh Lanta National Park and the remote pinnacle of Hin Muang.

​Koh Lanta National Park — turquoise lagoons & dramatic limestone formations

Koh Lanta National Park is known for its sheltered lagoons, underwater caverns, and vibrant coral slopes, making it a perfect starting point for our first dives of the season. Our check dive at Koh Haa set the tone, with chromodoris annulata and chromodoris kuniei decorating the reef like tiny jewels. Coral groupers hovered above bommies as juvenile angelfish and juvenile clown triggerfish darted around. Schools of yellowback fusiliers moved in waves alongside snappers and mackerels, while golden trevallies flashed past in hunting formation. A great barracuda cruised by, and a yellow-margin triggerfish paused at a cleaning station surrounded by busy wrasses and partner shrimps. Dusky damselfish, flutemouths and curious butterflyfish added movement and colour to the scene.

We continued south to Hin Muang for a spectacular wide-blue dive blessed with excellent visibility. Schools of batfish followed us down the wall where giant, bluefin and white-tongue trevallies patrolled the deep. Longnose emperors glided over purple-red soft corals, yellow boxfish played hide-and-seek around ledges, and a fimbriated moray eel peeked out from a crack. Rainbow runners flickered past like silver missiles while dogtooth tunas circled in the blue. A wandering octopus inspected our group before disappearing into the reef, and a white bent-stick pipefish blended perfectly with the soft coral background. Wrasses, anthias and red-toothed triggerfish filled every corner of the reef.
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Our final dives of the day took place at Koh Rok Ridge, where porcupinefish of every pattern — false-eye, blue-spotted, black-spotted and fine-spotted — hovered curiously. Blue-legged boxer shrimps and Durban dancing shrimps were busy in the crevices of the giant barrel sponges, one of which hid a massive giant moray eel. Yellowback fusiliers, yellow-lined snappers and giant trevallies passed in numbers, while anemonefish guarded their shimmering homes and hawkfish perched proudly on coral heads.

The night dive revealed an entirely different world. Giant hermit crabs marched across the sand, cleaning shrimps wiggled within the shadows of barrel sponges and delicate flabellinas crawled over the reef. Big red crabs explored the rocks, bubble corals sheltered tiny squat shrimps, parrotfish slept in their mucus cocoons and several triggerfish wedged themselves safely into cracks. A scribbled filefish drifted slowly through the torch beams while cardinalfish and soldierfish hovered along the walls.

We began again at Koh Haa Yai, the famous “Cathedral,” where the large caverns glowed with natural light. Cleaner pipefish hovered above sandy patches, yellow boxfish zig-zagged between boulders, and golden trevallies cruised through shoals of rabbitfish. Hermit crabs roamed along the rocky edges, tiger cowries shimmered on the walls, and Moorish idols danced gracefully in pairs. Surgeonfish, fairy wrasses and angelfish of all sizes added movement around the cathedral arches while another yellow-margin triggerfish watched us pass with suspicion.

Koh Haa Lagoon offered calm, crystal-clear water between islands 2 and 4. A giant moray eel and a yellow-edge moray eel shared the same patch of reef while Durban dancing shrimps and partner shrimps worked tirelessly at cleaning stations. Garden eels swayed like tall grass on the sandy bottom, convict blennies formed tight black-and-white tornadoes, and a red-marbled lizardfish watched for prey. Bearded scorpionfish lay perfectly still, and yellowfin soldiers hovered above the rocks. Two dogtooth tunas patrolled the perimeter while giant trevallies and juvenile emperor angelfish added flashes of yellow and blue. Wrasses, anthias, parrotfish and goatfish swirled across the lagoon.

At Koh Haa Chimney, we descended through the famous vertical tunnel before circling the large boulders outside. Yellow-lined snappers formed dense clouds, neon fusiliers streaked through the blue, and giant trevallies and dogtooth tunas swept along the deeper edges. A giant coral grouper patrolled the sandy bottom, and a proud peacock mantis shrimp marched boldly along the wall. Inside the entrance cave, nudibranchs glossodoris cincta and bornella anguilla decorated the rock while a graceful young banded sea snake hunted in the shallow 3-meter water as we finished the dive.
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Our sunset dive at Koh Haa Yai Reef was magical, with schools of Moorish idols, lined surgeonfish and copperband butterflyfish gliding above healthy hard corals and vibrant sea fans. Branching acropora, mushroom corals and large plate corals created perfect backdrops as the day slowly shifted into dusk.

A protected archipelago known for limestone cliffs, caverns & rich megafauna

Phi Phi National Park welcomed us with its dramatic limestone peaks and nutrient-rich waters.
Our first dive at Koh Bida Nok delivered an abundance of life. We found four tigertail seahorses clinging to sea fans, two banded sea snakes exploring crevices and a massive lobster hiding under a ledge. A beautifully patterned Dermatobranchus ornatus nudibranch crawled across a rock. Blacktip reef sharks glided by, and a resting leopard shark offered a serene moment. Schools of yellow-lined snappers and juvenile silver batfish danced in loose formation.

At Anemone Reef, the pinnacle was fully carpeted with blue, green and pink anemones swaying with the current, home to colourful anemonefish and porcelain crabs. Cometfish hovered above the reef while squids moved in formation. Yellowback fusiliers, neon fusiliers and yellow-lined snappers circled continuously while a fimbriated moray eel shared a crack with two white-eye morays. A yellow-edge moray eel and a copperband butterflyfish completed the scene.

Shark Point offered yet another highlight with gigantic pickhandle barracudas at a cleaning station, schools of blacktail barracudas, and a pair of pharaoh cuttlefish mating in the shallows. Large barrel sponges and elegant sea fans decorated the ridge. Fimbriated, white-eye and giant moray eels appeared one after another, while copperband butterflyfish played among the soft corals. Wrasses, anthias, damselfish and soft-coral gobies filled every corner of the reef.
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We then began our long navigation north — about 15 hours — following the coastline of Phuket and the Phang Nga region toward the Similan Islands.

 

Nine granitic islands with some of Thailand’s healthiest reefs

After a smooth 12-hour crossing, the iconic boulder landscapes of the Similans appeared on the horizon.
Our first dive at East of Princess Bay (Island 4) took us through Stonehenge, where large slabs of granite formed passageways filled with octopus, giant trevallies and juvenile oriental sweetlips. Lined surgeonfish moved calmly across the reef while peacock mantis shrimps patrolled the sand. Butterflyfish, angelfish, fairy wrasses and juvenile wrasses added colour at every turn.

West of Eden was spectacular with an ovula ovum cowrie mating on a coral head, schools of pennant coralfish weaving between boulders, and both yellowface and bluering angelfish showing off their vibrant colours. African coris and pastel ring-wrasse danced over the hard corals while a white-tip reef shark cruised by, followed closely by five imposing giant trevallies. Blue dragons decorated the coral blocks and a clown triggerfish impressed our divers. Gobies, chromis and small anthias flickered in the light.

At Hideaway, honeycomb groupers, peacock hinds, coral groupers and longface emperors dotted the reef, joined by oriental sweetlips and a mixed school of bluestreak and dory snappers. Durban dancing shrimps cleaned patiently below, while schools of juvenile blackfin barracudas and young bluefin trevallies hunted together with yellow-saddle goatfish.
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The night dive at West of Eden revealed sleeping parrotfish, squirrelfish, soldierfish, hunting morays, long-legged spiny lobsters, glossy nudibranchs and massive moon groupers patrolling the shadows. Cardinalfish, sweepers and nocturnal wrasses reflected the torchlight.

Honeymoon Bay (Island 4) greeted us with two octopuses mating in the sand channel. Dogtooth tunas circled the reef while cometfish, Durban dancing shrimps and partner shrimps explored the coral heads. A school of black-tail damselfish illuminated the water column, and a bright Halgerda tessellata nudibranch was the star of the macro search.

Back at West of Eden, we encountered another dogtooth tuna, a large green turtle and a small hawksbill turtle. Three more octopuses were spotted, including another mating pair. Leopard blennies peeked from holes while black-veined, dusky and two-coloured parrotfish grazed among the corals. Three-spot angelfish, hermit crabs and banded pipefish added to the action.

Elephant Head Rock delivered its signature swim-throughs, where giant trevallies roamed alongside giant yellow boxfish, porcupinefish, unicorn sweetlips, Andaman sweetlips, six-banded angelfish, rabbitfish, spotted boxfish and map puffers.
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Our sunset dive at Turtle Rock (Island 8) featured brassy drummers, more giant yellow boxfish, black surgeonfish, blackear wrasse, spotted-tail dart gobies, porcelain crabs, marble groupers, coral groupers, tiger cowries and a parade of parrotfish grazing the reef. A pygmy squid darted in and out of view, and an octopus displayed brilliant colors as it hunted among the rocks.

Eagle’s Rock surprised us with beautiful coral bommies and granite formations sheltering giant morays, bluefin trevallies, dogtooth tunas and sail-finned surgeonfish. A tiny juvenile rockmover wrasse danced hypnotically across the sand.

At Donald Duck Bay, we explored the iconic boulders and giant barrel sponges where peacock mantis shrimps peeked out from holes. Dogtooth tunas, bluefin trevallies, giant morays, clownfish, blue dragons, sail-finned surgeons, sea fans, puffers, hawkfish, cometfish and oriental sweetlips kept us entertained. A tiny teardrop butterflyfish juvenile danced near the surface.

Back to Elephant Head Rock for our third dive of the day, we crossed paths with a white-tip reef shark, slender groupers, lizardfish, coral groupers, giant trevallies, bluefin trevallies and huge schools of neon fusiliers lighting up the blue.
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Our blackwater dive was a festival of planktonic life — larval mantis shrimps, long chains of siphonophores, crab larvae, salps carrying tiny fish companions, squids, larval anemones, larval triggerfish, eel larvae, drifting jellyfish and countless shrimp and spreadfish. Even a tiny larval lizardfish appeared under our lights.

Our last morning at Honeymoon Bay was peaceful with a gentle zebra shark resting on the sand. Parrotfish, rabbitfish, wrasses and schools of fusiliers glided calmly above the reef while gobies, blennies and butterflyfish added colour to the shallows.
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Boonsung Wreck, as always, was a fish soup of the highest order. Clouds of juvenile yellowback fusiliers, neon fusiliers and blue-striped snappers filled every corner while juvenile silver batfish shimmered around the structure. Porcupinefish floated in groups like balloons, honeycomb and white-eye moray eels peeked from the metal plates, pompano hunted through the clouds of fish and big-eye trevallies zig-zagged through the chaos. Chromodoris kuniei and bright Halgerda nudibranchs crawled along the beams as damsels, wrasses and parrotfish weaved through the dense schools.We surfaced from our final dive tired, happy and already eager for the next adventure, ending our trip at Tap Lamu Pier with big smiles all around.