This 8-day south-to-north Andaman liveaboard charter offered an exceptional cross-section of Thailand’s Andaman Sea diving. From calm lagoons and dramatic southern pinnacles to the fish-rich northern marine parks and legendary Richelieu Rock, the trip combined pelagic action, rare macro life, vibrant coral reefs and relaxed liveaboard living. Calm seas and good visibility throughout allowed us to fully enjoy each site with our private group of US guests.

Day 1 – Phuket to Koh Haa Lagoon
We welcomed our guests aboard in Phuket before departing toward Koh Haa Lagoon. The afternoon was spent settling in, assembling dive gear, and enjoying the first sunset at sea as we cruised south. Anticipation built for the check dive scheduled for the following morning in the calm, protected lagoon.

Day 2 – Koh Haa, Hin Daeng & Hin Muang
Our check dive at Koh Haa Lagoon provided ideal conditions to ease into Andaman diving. A hawksbill turtle cruised past the reef while a blacktip reef shark patrolled the edge of the lagoon. Moray eels peered from coral heads, including a memorable sighting of a moray eel swimming freely across the sand. African pompano and longnose emperors passed through the blue, while oriental and harlequin sweetlips hovered near the reef. Macro highlights included a black cat headshield slug and a delicate Fabalina nudibranch. Wrasses, parrotfish, butterflyfish, angelfish, surgeonfish and clouds of damselfish filled the shallow reef.
The second dive at Hin Daeng delivered immediate big-fish energy. Schools of batfish glided along the drop-off, surrounded by bluefin trevallies, giant trevallies, rainbow runners and barracuda. Potato groupers rested on ledges, while redtooth triggerfish, juvenile angelfish and schooling bannerfish animated the reef. Honeycomb and snowflake moray eels hid among soft corals, while ghost pipefish, spotted Hypselodoris, anemone clownfish and anemone crabs rewarded careful observation.
At Hin Muang, the third dive featured strong currents and excellent fish life. Dogtooth tuna and golden trevallies cruised past in the blue, joined by milkfish and schools of naked fusiliers. Batfish hovered near the pinnacle as glassfish swirled tightly around coral outcrops, constantly harassed by hunting jacks. Coral groupers, a shy lobster, multiple ghost pipefish and a striking juvenile emperor angelfish completed the scene.
Our night dive revealed a different side of the reef. Hunting moray eels, including bartail and snowflake morays, moved actively across the coral. A resting hawksbill turtle, yellow boxfish and a cruising barracuda were highlights, while the reef came alive with macro life such as tiger cowries, Mauritia arabica immanis, Willey’s Halgerda, bicolor Fabelina, Jebb’s flatworm and sapsucking slugs.

Day 3 – 8 Mile Rock, Stonehenge & Koh Sawang
​
Two morning dives at 8 Mile Rock delivered classic Andaman schooling action. Great barracudas cruised above the reef while schools of yellow snappers, bigeye trevallies and bluefin trevallies moved in unison. Red-bar anthias coloured the reef, joined by marbled groupers, fimbriated moray eels and ghost pipefish. Allied cowries and Chromodoris nudibranchs added macro interest among hard corals, sea fans and sponges.
The third dive at Stonehenge showcased its famous soft-coral formations in full colour. Layers of red, orange and purple soft corals covered the structures, sheltering flounders, tomato clownfish and a black-gill Phestilla nudibranch. A Kuhl’s stingray rested on the sand while a massive sea snake moved calmly through the reef. Schools of snappers, wrasses, parrotfish and fusiliers filled the water column.
Our final dive of the day at Koh Sawang focused on critter life. A huge spearer mantis shrimp was the standout, accompanied by yellow boxfish, porcupinefish, rabbitfish, whip coral shrimp and squat shrimp. Bluefin trevallies continued to patrol the deeper sections of the site.

Day 4 – Hin Muang, Hin Daeng & Koh Haa Cathedral
Returning south for one final day before heading north, Hin Muang once again delivered strong action with ghost pipefish, rainbow runners, batfish, tuna and great barracudas. A dramatic moment unfolded as predatory fish hunted inside a dense glassfish bowl. Spiny lobsters and redtooth triggerfish were common along the reef.
At Hin Daeng, ornate ghost pipefish were spotted among soft corals while yellowtail and dogtooth tuna hunted glassfish in the blue. Schools of batfish, oriental sweetlips, milkfish and juvenile emperor angelfish moved across the drop-off, accompanied by honeycomb morays and redtooth triggerfish.
The third dive at Koh Haa Cathedral featured impressive swim-throughs and beams of light cutting through the cave. Giant and snowflake moray eels hid among the rocks, while potato groupers rested near the entrance. Bluefin trevallies, schools of yellow snappers, a passing reef shark and Spanish mackerel cruised by. Macro highlights included Halgerda tessellata, baby boxfish and sea cucumbers scattered across the reef.
That evening, we began our transit north toward the Similan Marine Park.

Day 5 – Similan Islands & Koh Bon
​
At Sharkfin Reef, hawksbill turtles cruised along the granite boulders, accompanied by longnose emperors, bluefin trevallies and schools of neon and lunar fusiliers. Flatworms, wrasses, parrotfish, butterflyfish and surgeonfish filled the reef.
West of Eden (Similan Island #7) offered a lush reefscape. Giant moray eels, peacock mantis shrimp, brown marbled groupers and baby honeycomb morays were spotted alongside red fire gobies, flasher wrasse, cornetfish, starry dragonets and African sand wrasse. Two turtles passed slowly through the reef while schools of fusiliers streamed overhead.
At Three Trees (Similan Island #9), bird wrasses, clown triggerfish, big jobfish and a Napoleon wrasse dominated the dive, joined by an eagle ray gliding through the blue and several cornetfish cruising between bommies.
Our sunset dive at Koh Bon Ridge and Reef brought giant trevallies hunting among glassfish, massive schools of emperors, fusiliers, Andaman sweetlips, angelfish and coral groupers as the light faded.

Day 6 – Koh Bon, Koh Tachai & Night Dive
Morning dives at Koh Bon Pinnacle and West Ridge were packed with schooling fish. Batfish, barracudas, bluefin trevallies, giant trevallies, bannerfish and butterflyfish surrounded the pinnacle, joined by coral groupers, lionfish, emperors and double-spotted queenfish. Yellow goatfish hunted alongside trevallies, while moray eels and tuna patrolled the reef edges.
After cruising north, we reached Koh Tachai Plateau, where schools of barracuda, GTs, bluefin trevallies and dogtooth tuna dominated the dive. A hawksbill turtle passed by, followed by a large Jenkins whipray. Juvenile and adult clown triggerfish, royal angelfish, brown marbled groupers and batfish completed the scene.
The night dive at Koh Tachai Reef was a standout. Five blacktip reef sharks remained with the divers for 30–40 minutes, while checkered, mangrove and red snappers actively hunted. Fusiliers, barracuda, lionfish and another turtle encounter made for an unforgettable evening dive.

We also went on a Blackwater dive that night and it didnt disappoint with its fair share of cephalopods, crustaceans and juvenile fish! 

Days 7 & 8 – Richelieu Rock
A full two days of diving at Richelieu Rock delivered everything the site is famous for. The “gang” of giant trevallies, longnose emperors and rainbow runners hunted together through clouds of glassfish and fusiliers. Schools of barracuda, amberjacks and batfish circled the pinnacles, while coral groupers and sweetlips occupied the reef.
Macro life was exceptional: thorny seahorses, octopus, jawfish, harlequin shrimp, cleaner pipefish, orange-spotted pipefish, ornate sapsucking slugs, Dermatobranchus and Nendronotis species, tiger egg cowries, spearer mantis shrimp and juvenile clown triggerfish were all recorded. Additional sightings included juvenile blue triggerfish and ridged dermatobranchs.
The final two dives on Day 8 brought more jawfish, thorny seahorses, octopus, schools of barracuda and batfish, peacock-tail shrimp and mole cowries—an ideal conclusion to the trip.
After the last dive, we cruised north to Ranong, where guests disembarked, bringing this South-to-North Andaman journey to a close.

​A classic north-to-south Andaman crossing, mixing iconic pinnacles, colourful reefs and relaxed lagoon dives, with a great group of guests from Israel travelling accompanied by Ian, our partner at Dive Buddy Agency. Eight days of variety, big fish action, macro treasures and vibrant reefs, all stitched together by calm seas and excellent visibility.

​We welcomed our guests in Ranong before the boat briefing and an early afternoon departure toward the Surin National Park. As the coastline faded behind us, anticipation grew for the first dives of the trip and the promise of healthy reefs and rich marine life ahead.

Our check dive at Koh Chi gently introduced everyone to Andaman conditions. A shy hawksbill turtle cruised past the reef while false anemonefish hovered over their hosts. Batfish glided between bommies, giant moray eels peeked from crevices, and schools of bannerfish mixed with yellowback and naked fusiliers. Blue sea stars, sea urchins, leopard sea cucumbers and table corals carpeted the reef, joined by powder-blue angelfish, longnose butterflyfish and clouds of damselfish.

Dives two and three took place at Richelieu Rock, which was in full celebration mode. Three harlequin shrimps were busy with their sea star meals, while Chromodoris annulata, Cuthona sibogae and ghost pipefish added delicate details to the scene. Around them swirled the famous Richelieu gang: giant trevallies, bluefin trevallies, bigeye trevallies, rainbow runners, chevron barracudas and dense schools of yellowback and neon fusiliers. Glassfish shimmered around the pinnacles, constantly harassed by hunting jacks, while coral groupers, peacock groupers, batfish and sweetlips filled every layer of the reef. Soft corals, sea fans and hard coral bommies completed the festival atmosphere.
​
Our night dive at Bungalow, on the west side of Surin South, revealed a different mood. Giant lobsters roamed freely in the dark, black flatworms crept over the sand, brittle stars unfolded their arms and a small whitetip reef shark patrolled silently along the edge of the reef.

Two morning dives at Koh Tachai Pinnacle delivered excellent visibility and constant motion around the main, second and third pinnacles. Giant trevallies, bluefin and golden trevallies hunted alongside rainbow runners and dogtooth tuna. Schools of fusiliers, including yellowback, scissortail, neon and variable-lined fusiliers, streamed past in silver ribbons, mixed with five-lined snappers and goatfish. Marble groupers were joined by coral groupers and peacock groupers, while triggerfish, blennies, wrasses and parrotfish animated the reef. Sea stars, feather stars and soft corals clung to the granite slopes.

The third dive explored Koh Bon Pinnacle and North Ridge. Maldivian sponge snails decorated the rocks, surrounded by schools of fusiliers and sea chubs, humpnose big-eye bream and longnose emperors. Squat shrimps and anemone crabs hid among soft corals with Clark’s anemonefish, while sweetlips and multiple snapper species hovered above the reef.
​
At sunset, Koh Bon Ridge and Bay came alive with octopus activity and a colony of Haminoea cymbalum. Giant lobsters, moray eels, sweetlips, wrasses, parrotfish and triggerfish emerged as the light faded. During the crossing to the Similan Islands, a pod of dolphins escorted the boat, riding the bow wave almost the entire way.

The day began at Three Trees, where massive barrel sponges crowned deep boulders covered in pink and purple soft corals. Garden eels danced above the sand as dogtooth tuna patrolled the blue. Bluefin trevallies, Durban dancing shrimps, a young hawksbill turtle and blue-spotted stingrays rounded out the scene, joined by sweetlips, wrasses, parrotfish, fusiliers, snappers, basslets, groupers, butterflyfish, angelfish and surgeonfish.
​
At Elephant Head Rock, a young hawksbill turtle rested inside a swim-through while blue ribbon eels waved from the sand. Trevallies and emperors cruised past large granite formations dotted with hard corals and sea fans.
West of Eden offered a lush reefscape with banded sea snakes, blackspotted and oriental sweetlips, and Thuridilla undula. Wrasses, parrotfish, fusiliers, snappers, basslets, groupers, angelfish, triggerfish, rabbitfish and moray eels filled the coral gardens.

Koh Haa Lagoon welcomed us with calm water and beautiful light. Tigertail cowries, a colony of Chelidonura on the sand, common porcupinefish and oriental sweetlips shared the lagoon with wrasses, parrotfish, fusiliers, snappers, basslets, small groupers, butterflyfish, angelfish and surgeonfish. Sea cucumbers and sea urchins dotted the sandy patches between coral heads.

At Koh Haa Yai, also known as Cathedral, Bornella anguilla hid deep inside the cave, while Phidiana militaris waited at the exit. Multiple Phyllidia species and Glossodoris cincta adorned the walls. Schools of checkered snappers, bluefin trevallies and batfish circled outside, while coral groupers and fusiliers moved through shafts of light. Jellyfish drifting nearby attracted filefish and naked fusiliers.

Hin Muang revealed juvenile ghost pipefish among soft corals, surrounded by sweetlips, wrasses, parrotfish, fusiliers, snappers, basslets, groupers, butterflyfish, angelfish, triggerfish and moray eels.
​
The sunset dive at Hin Daeng closed the day with schools of batfish, anemone crabs tending Clark’s anemonefish eggs, giant moray eels and golden trevallies, all set against a backdrop of red soft corals, sea fans and busy reef life.

Our first dive at Hin Paad, also known as Eight Mile, revealed a unique reef coated in yellow and green hard corals, mainly lettuce coral and sheet coral. Curious great barracudas, schools of jacks, rainbow runners and giant trevallies cruised by, while ghost pipefish hovered near the reef. Fusiliers filled the water column, and white-eye and fimbriated moray eels patrolled the cracks, joined by angelfish, butterflyfish, scorpionfish and surgeonfish.

At Koh Adang Rock, the dive shifted between muck and boulders. Chromodoris risbecia pulchella, scorpionfish, elegant crinoid squat lobsters and translucent porcelain crabs nestled inside purple soft corals, with sea stars and feather stars scattered across the slope.
​
Stonehenge delivered its trademark colours, with layers of red, orange, yellow, purple, blue, green and white soft corals covering the structures. Tigertail seahorse clung to gorgonians, various damselfish defended their territories, and common porcupinefish hovered above the reef. Lionfish, sea urchins, wrasses, parrotfish and triggerfish completed the vibrant scene.

While one group enjoyed a sunset dive at Koh Taru with familiar reef residents and hunting moray eels, others opted for a blackwater dive off Koh Lipe. Remoras searched for hosts, tiny squids flashed and released ink, and larval fish, jelly creatures and drifting crustaceans floated through the darkness.

At Koh Rock Reef, octopus explored the reef among giant barrel sponges. Schools of naked and yellowback fusiliers streamed past black surgeonfish, Durban dancing shrimps and giant moray eels. Juvenile lobsters hid in cracks alongside wrasses, parrotfish, butterflyfish and angelfish.

The second dive split between Hin Daeng and Hin Muang. Bornella anguilla reappeared at Hin Muang, while both sites delivered schools of batfish, rainbow runners and giant trevallies against dramatic drop-offs covered in soft corals.
​
Our third dive at Koh Haa Yai, Cathedral, featured giant moray eels tucked inside barrel sponges, Chromodoris annulata and Risbecia pulchella decorating the walls, and steady schools of fusiliers and snappers circling the entrance.

Our final dive of the day took us back to Koh Haa Neua and its famous Chimney, a vertical swim-through packed with life from top to bottom. Along the walls, we spotted Cuthona siboage and doriprismatica atromarginata (glossodoris) while a juvenile two-color parrotfish hovered cautiously near the coral. Moray eels were hidden deep inside the chimney, accompanied by scorpionfish, blennies and curious wrasses peeking out from the cracks. Above the opening, schools of fusiliers and snappers cruised by, joined by sweetlips, angelfish, butterflyfish, triggerfish, surgeonfish and groupers. Seastars, sea cucumbers and sea urchins dotted the reef, and the entire structure was coated in a beautiful mix of soft corals and hard corals, providing a colorful and serene end to the diving day.

​One last dive at Shark Point rounded off the trip with blue-spotted stingrays, snowflake moray eel, schools of snappers, fusiliers, butterflyfish, angelfish and clouds of glassfish over healthy hard corals and sea fans. After surfacing, we headed to Chok Thaworn Pier in Phuket to say goodbye to our Dive Buddy group, closing a memorable North and South Andaman journey aboard the MV Smiling Seahorse.

​After clearing Thai immigration in Ranong, we welcomed our international group, from Taiwan, Japan, France, Russia, USA, Norway, Spain and India on board and set course north toward Myanmar. Following a smooth immigration process in Kawthung, the Smiling Seahorse slipped into the vast maze of the Mergui Archipelago. Hundreds of islands, mangroves, and untouched reefs stretched around us as we sailed deeper into a region where tides and currents still dictate the rhythm of life. The evening was spent settling in, enjoying sunset on deck, and anticipating the first dives of the trip. Thanks for all the lovely photos you've shared, we've added a few more from previous trips to illustrate this blogpost and what was spotted this week :)

Our first two dives took place at South Twin Reef. Stonefish lay perfectly camouflaged on the reef, while a shy turtle cruised past before disappearing into the blue. Giant trevallies and rainbow runners swept through the current, and yellow-edged moray eels queued patiently at cleaning stations, mouths wide open like clients at an underwater dentist. Durban dancing shrimps, peacock mantis shrimps, blue sea stars, Indian cushion sea stars, Persian carpet flatworms, giant moray eels and bar-tail moray eels filled the reef with life. Schools of neon fusiliers, bannerfish, striped bristletooth surgeonfish and flashes of blue dragons completed the scene.
​
Dive three brought us to North Twin Reef, where a vast granite plateau drops into coral bommies growing around and on top of the rock. Here we encountered gold-dotted flatworms, Maldivian sponge snails, blue dragons, Chromodoris annulata, and a giant moray eel enjoying a meticulous cleaning session by a banded boxer shrimp. Schools of yellowback fusiliers and naked fusiliers streamed over the reef.

​We dedicated the entire day to Black Rock, one of the most iconic dive sites of the Mergui Archipelago. The dives were packed with action: Bornella anguilla, anemone crabs, Clark’s anemonefish, and large schools of juvenile yellowback fusiliers mixed with naked fusiliers. We observed octopus mating, bearded scorpionfish, lionfish, peacock-tail anemone shrimps, squat shrimps and banded boxer shrimps. A yellow frogfish sat motionless on the reef, while zebra moray and tiger snake moray eels patrolled the rocks. Juvenile sweetlips hovered nervously, mackerels zipped past, and giant trevallies with rainbow runners dominated the blue.
​
Dive two delivered a memorable highlight as oceanic mantas glided overhead, circling gracefully before vanishing into the deep. We ended the day with a festive BBQ on board, celebrating the final hours of 2025 while sailing toward Three Islets.

The first morning of 2026 began with stunning dives at Submarine, Shark Cave, and Square. Schools of naked fusiliers, juvenile yellowback fusiliers, neon fusiliers and blue-striped fusiliers filled the water column. Bamboo sharks rested under ledges, while octopus roamed the reef. Yellow-and-black tiger-tail seahorses, including juveniles, clung to the reef, alongside colonies of Chromodoris fidelis. We also encountered schools of yellowtail barracuda, scorpionfish, devil scorpionfish, banded snake eels, fimbriated and honeycomb moray eels, Cuthona sibogae, orange-spotted pipefish, Durban dancing shrimps, banded boxer shrimps and a marble ray cruising by.
​
In the afternoon, we went ashore at Kyun Phila (Phila Island) to visit the local village, temple and beach, before returning to the boat for our first night dive of the year. The night dive delivered starry night octopus, five tiger-tail seahorses including two juveniles (one completely white), ambon crinoid shrimps, bubble shrimps, blunt decorated crabs, sleeping parrotfish cocooned in the reef, resting triggerfish wedged into rocks, soldierfish and squirrelfish emerging from crevices, and hunting moray eels cruising the sand.

Our first two dives took place at Seafan Forest. Pharaoh cuttlefish and broadclub cuttlefish hovered over the reef, while trevallies, rainbow runners and mackerel passed by in the blue. Emperor fish, peacock mantis shrimps, Chromodoris albopunctata mating, Chromodoris annulata, black frogfish, Chelidonura punctata and perfectly hidden stonefish kept everyone busy. Two dive groups also retrieved a large ghost net from the reef, a meaningful conservation effort.

The reef was alive with toby puffers from the Andaman Sea, porcupinefish, sharpnose puffers, titan and yellowmargin triggerfish, bullethead and steephead parrotfish, moon and cleaner wrasses, yellow and bluefin goatfish, combtooth blennies, coral and peacock groupers, white-eye moray eels, powder-blue and ringtail surgeonfish, blueface angelfish and pennant butterflyfish.

Dive three at Western Rocky, exploring the Cave, Islets and Eagle’s Rock, revealed pharaoh cuttlefish laying eggs deep in the rock, a giant moray eel waiting in the cave, cleaning shrimps, blunt decorated crabs, reef crabs, Durban dancing shrimps, Chromodoris annulata, Hypselodoris bullockii, Moridilla brocki and blue dragons. Wrasses were actively attacking sergeant major eggs in a lively display of reef drama.

Our first dive at Dendro’s Peak featured dogtooth tuna, rainbow runners, giant trevallies and narrow-barred Spanish mackerel (Scomberomorus commerson). Pharaoh cuttlefish and stonefish shared the reef with streaming fusiliers, bluefin trevallies, coral groupers, longnose butterflyfish, cleaner wrasses and large barrel sponges sheltering clouds of glassfish.

Back at Sea Fan Forest, we encountered stonefish, cuttlefish, rainbow runners, peacock mantis shrimps hunting, Chromodoris annulata, Halgerda tessellata and Glossodoris hikuerensis. Giant sea fans covered in purple soft corals dominated the landscape, surrounded by schools of fusiliers, bannerfish, yellowtail butterflyfish, wrasses, blennies and juvenile angelfish hiding deep within the reef.

At Western Rocky, ghost pipefish drifted along the reef, alongside Bornella anguilla, Chromodoris annulata with eggs, Chromodoris risbecia tryoni with eggs, a giant moray eel waiting at the cave exit, Persian carpet flatworms mating, juvenile chromodoris and Flabellina bicolor.
​
The night dive delivered ghost pipefish, big red reef crabs, a tiger cowrie gliding openly across the rock, massive Glossodoris hikuerensis with eggs, Chromodoris annulata, giant moray eels preparing to hunt, dark flatworms, squat shrimps, hermit crabs, leopard sea cucumbers, red sea stars and Indian cushion sea stars.

 ​Often nicknamed “Volcano” by divers, our final dive site is in fact Shark Lagoon, a spectacular collapsed rocky formation rather than a true volcanic crater. We entered the lagoon to admire the dramatic rock amphitheatre before starting our final dive along a sponge- and soft-coral-covered wall shaped by erosion and time. Chromodoris fidelis, tiger-tail seahorses, blue dragons, Risbecia pulchella, blue-ringed angelfish, two-lined spinecheeks, gold-saddled rabbitfish, dark surgeonfish and comet longfin fish accompanied us along the reef.

​Giant barrel sponges, purple and pink soft coral trees, schools of fusiliers, hawkfish, coral groupers, cleaner shrimps and swirling clouds of glassfish completed a calm, colorful, and fitting finale to our New Year journey in the Mergui Archipelago. After surfacing, we began our journey back toward civilisation, carrying with us memories of pristine reefs, festive New Year celebrations at sea, and unforgettable encounters in the wild heart of the Mergui Archipelago.

Our check dive took place at Koh Chi Reef, part of the Surin Islands. These remote islands are home to the Moken people, sea nomads who have lived in harmony with the ocean for generations. Shallow reefs, sandy slopes and healthy coral gardens make this area ideal for a gentle start.
With crystal-clear visibility, we encountered an abundance of reef life: false anemonefish, Clark’s anemonefish, moray eels, damselfish, cleaning shrimps, garden eels dancing in the white sand, and schools of five-lined snappers. Parrotfish such as blue-barred parrotfish and bullethead parrotfish grazed the reef, while small groupers including coral groupers and peacock groupers hovered near coral heads. Wrasses were everywhere: cleaner wrasse, moon wrasse, and sixline wrasse flashing between rocks. Our snorkellers were rewarded with an exciting sight: three blacktip reef sharks hunting in the shallows.

We then headed to the legendary Richelieu Rock for dives 2, 3, and our night dive. This isolated limestone pinnacle rises from deep water and acts as a magnet for pelagic life and dense reef action.
The gang was fully assembled: giant trevallies, bluefin trevallies, bigeye trevallies, large schools of rainbow runners, batfish, and hunting yellowtail barracuda and chevron barracuda. Morays were everywhere, from white-eye moray eels to fimbriated moray eels and massive giant moray eels. We spotted juvenile clown triggerfish, schools of yellowback fusiliers and two-spot fusiliers, five-lined snappers, along with Chromodoris annulata and its eggs, Chromodoris geometrica, and Cuthona sibogae.
​
Night dive: a true nudibranch festival. Crabs and shrimps emerged, white-eye moray eels hunted actively, octopus roamed the reef, and Glossodoris atromarginata glided over sponges. Sleeping fish included parrotfish wrapped in mucus cocoons, squirrelfish, soldierfish, and sweetlips tucked under ledges, while Spanish dancers and hunting lionfish completed the nocturnal scene.

Dive 1: Koh Bon Pinnacle
Massive schools of fusiliers surrounded the pinnacle: yellowback fusiliers, gold-striped fusiliers, neon fusiliers, manylined fusiliers, and blue and gold fusiliers. Dogtooth tuna patrolled the blue, joined by small mackerels and passing barracudas. On the reef we found peacock mantis shrimp, stunning yellow and pink soft corals, and excellent visibility. Groupers included coral groupers, peacock groupers, and yellow-edged groupers. Parrotfish such as steephead parrotfish, blue-barred parrotfish, and bullethead parrotfish grazed constantly, while wrasses like African coris, moon wrasse, and bird wrasse mixed with clouds of damselfish.

Dive 2: Koh Bon Ridge and Bay
A rare highlight: octopus mating. Giant moray eels hunted in open water, batfish cruised slowly, and inside the bay we found the beautiful sea slug Haminoea cymbalum. Common reef fish included powder-blue surgeonfish, lined surgeonfish, oriental sweetlips, copperband butterflyfish, and schools of glassfish.

Dive 3: Koh Tachai Pinnacle
A high-energy dive with huge schools of giant trevallies, bluefin trevallies, and bigeye trevallies, swirling alongside dense barracuda formations. A giant grouper dominated the scene, while the boulders hid numerous giant lobsters. We also spotted blueface angelfish and royal angelfish, surrounded by schools of yellowback, twinstripe, and neon fusiliers. Reef life included potato groupers, coral groupers, parrotfish, wrasses, and clouds of anthias.
​
Dive 4: Tachai Reef
A calmer end to the day with a blacktip reef shark, a baby hawksbill turtle, and classic reef fish: surgeonfish, butterflyfish, wrasses, triggerfish, and schools of fusiliers sweeping over the reef.

Back at Richelieu Rock, the gang returned in full force: trevallies, rainbow runners, barracudas, and hunting tuna. Nudibranch highlights included Chromodoris risbecia pulcella, Elysia ornata, Cuthona sibogae, and Chromodoris annulata. We saw cleaner pipefish, octopus, massive schools of yellowback fusiliers, naked fusiliers, rabbitfish, glassfish under constant attack from predators, blue ribbon eels, harlequin shrimps, and endless fish action.
​
Dive 4 – Sunset at Surin South (“Bungalow”)
A magical sunset dive featuring Cuthona sibogae, epaulette surgeonfish, lined surgeonfish, oriental sweetlips, massive painted spiny lobsters, orange-banded pipefish, Thuridilla undula, Halgerda tessellata, Flabellina sp., Chromodoris geminus. Pelagics included pompano, dogtooth tuna, and schools of yellowback, twinstripe, and neon fusiliers, along with ring angelfish, blueface angelfish, and a cruising Napoleon wrasse.
Other groups experienced a blackwater dive: salps, mantis shrimp larvae, juvenile squids, crab larvae, snapper larvae, cornetfish larvae, and drifting siphonophores. Pure plankton poetry.

Dive 1: Torinla Pinnacle
An exceptional final morning: Andaman sweetlips, mating Kuhl’s blue-spotted stingrays, yellow-edged lyretail groupers, peacock groupers, coral groupers, black-saddle groupers, juvenile peacock mantis shrimp, anemone crabs, Clark’s anemonefish, titan triggerfish, and bluespine unicornfish.
​
Final dive: Richelieu Rock
A grand finale with everything Richelieu is famous for: massive schools of trevallies and rainbow runners, dense barracuda formations, naked, neon, yellow back yellow lined fusiliers in every direction, hunting tuna, batfish, morays, nudibranchs, glassfish clouds, and that unmistakable feeling of being inside one of the most alive dive sites in the Andaman Sea.
 

​We left Ranong’s Badin Pier after clearing Thai immigration, welcoming guests from France, Greece, Germany, USA, Malaysia, Singapore, Belgium, Ireland, and Italy. After a smooth Burmese immigration process in Kawthung, the Smiling Seahorse headed north into the Mergui Archipelago, a remote labyrinth of jungle-covered islands, quiet bays, and rarely visited reefs where diving still feels like exploration.

​Our check dive and second dive took place at South Twin Reef, easing everyone back into the water with a mix of macro and reef life. Flabellina and Chromodoris annulata covered the walls, while squat shrimps and Durban dancing shrimps shared space with peacock mantis shrimps. Schools of lined surgeonfish and ringtail surgeonfish cruised over the reef, joined by neon fusiliers and yellowback fusiliers. Dogtooth tuna patrolled the blue, giant moray eels peeked from the rocks, and batfish hovered calmly nearby, while tiny juvenile anemonefish added delicate flashes of pink.
Dive three brought us to North Twin Reef, where octopus activity was high, giant moray eels dominated the crevices, and Chromodoris annulata appeared again along the reef. A few coral groupers, powder-blue surgeonfish, and titan triggerfish completed the scene.
The night dive in North Twin Bay was pure atmosphere. Curious octopus, squids, jellyfish sheltering tiny fish, big red reef crabs, scorpionfish, and bar-tail moray eels filled the darkness. Parrotfish and triggerfish were found sleeping, firmly wedged into the rock, their trigger spine locked in place to keep predators at bay, a perfect example of reef survival after sunset.

​We spent the full day at Black Rock, a dramatic offshore pinnacle where deep water, currents, and open ocean life constantly rewrite the dive plan. Morning dives were rewarded with curious oceanic manta rays circling above the reef, accompanied by schools of chevron barracuda, blacktip trevallies, bluefin trevallies, golden trevallies, and bigeye trevallies. Great barracuda, giant moray eels, yellow-edged moray eels, and shy batfish added to the excitement, while coral groupers, peacock groupers, powder-blue surgeonfish, and velvet surgeonfish filled the reef.
Macro life was everywhere, with anemone crabs, cleaner shrimps, squat shrimps, bearded scorpionfish, and colorful nudibranchs. Neon fusiliers and yellowback fusiliers formed dense clouds around the pinnacle, constantly shifting with the current.
The night dive revealed a different Black Rock, with pygmy squid hunting shrimps, devil scorpionfish, bar-tail moray eels, sleeping parrotfish, rabbitfish, and a stunning collection of cowries including tiger cowrie, money cowrie, and mole cowrie, along with basket stars and sea cucumbers carpeting the reef.

​We explored Three Islets, diving Submarine, Shark Cave, and Square. At Submarine, bamboo sharks rested calmly while cleaner pipefish and orange-spotted pipefish hovered above the reef. Schools of neon fusiliers, yellowback fusiliers, slender fusiliers, and twin stripe fusiliers mixed with chevron barracuda and passing trevallies including giant trevally, bluefin trevally, and golden trevally. A cobia hid among rainbow runners, while wahoo and mackerel cut through the blue. One lucky group even witnessed a whale shark cruising through the main channel.

​Shark Cave delivered classic scenes of tomato anemonefish and Clark’s anemonefish guarding their eggs, anemone crabs, white-eye moray eels, schools of fusiliers, and wrasses repeatedly harassing sergeant majors protecting their nests.
At Square, tiger-tail seahorses stole the show alongside orange-spotted pipefish, golden trevallies, yellowtail barracuda, batfish, and spider crabs. The night dive added decorated crabs, sea snakes, cone snails, gorgonian crabs, and glowing nudibranchs to the mix.
After the final dive, we set course west toward the legendary Burma Banks, a remote chain of offshore seamounts rising from deep water and known for shark encounters and wide-open pelagic scenery.

​At Row Bank, adult and juvenile nurse sharks dominated the dives, cruising effortlessly above sandy slopes. Powder-blue surgeonfish and lined surgeonfish moved across the reef alongside oriental sweetlips and two-spot butterflyfish. Around the coral heads, coral groupers and peacock groupers patrolled calmly, while cleaner wrasse and sixline wrasse stayed busy at their stations. Between the rocks, leopard blennies and fang blennies popped in and out, joined by flashes of royal dottybacks adding color to the shadows.
At Rainbow Bank, the scene remained wide open and shark-filled, with more nurse sharks gliding past mangrove snappers and schools of humpback unicornfish and sleek unicornfish. The reef itself was alive with pastel ringwrasse, moon wrasse, and African coris sweeping over the bottom, while chalk bass and royal dottybacks hovered close to the structure. Tiny blennies guarded their holes as blue and gold fusiliers streamed overhead.
The final two dives at Coral Bank brought white-tip reef shark into the mix, accompanied by powder-blue surgeonfish, epaulette surgeonfish, and golden rabbitfish grazing along the reef. The smaller life stole the show here, with cleaner wrasse, blackear wrasse, dragon wrasse, leopard blennies, chalk bass, royal dottybacks, and juvenile damselfish filling every crevice, turning these quieter dives into beautifully detailed reef explorations.

​Three dives at Silvertip Bank delivered classic big-bank scenery with nurse sharks, silvertip reef sharks, bigeye emperors, powder-blue surgeonfish, lined surgeonfish, and humpback unicornfish cruising above the reef. Macro highlights included nudibranchs and a tapestry shrimp hiding inside a giant clam, while mappa pufferfish drifted lazily by.
The evening ended with a blackwater dive, revealing larval flounder, larval mantis shrimp, post-larval porcupinefish, flying fish larvae, pencil squid, purple-back squid, larval anemones, siphonophores, comb jellies, and clouds of drifting plankton glowing in the darkness.

​At Sea Fan Forest, giant purple soft corals and towering sea fans framed stonefish, sleeping giant moray eels, rainbow runners, and schools of neon fusiliers and yellowback fusiliers. The reef was alive with coral groupers, peacock groupers, wrasses, blennies, parrotfish, and triggerfish weaving through the coral forest.
The second dive turned into a true team effort as most divers joined a successful ghost net removal, freeing the reef from a massive abandoned net.
The afternoon and sunset dives at Western Rocky, covering the Islets, the Cave, and Eagle’s Rock, delivered schools of trevallies, fusiliers, yellowtail barracuda, lionfish, scorpionfish, titan triggerfish, ghost pipefish, giant moray eels, harlequin shrimps, and a spectacular Glossodoris cincta laying eggs. The day ended with our traditional BBQ and boat party under the stars.

​Our final dive took place at Dendro’s Peak, where pharaoh cuttlefish, giant moray eels, Clark’s anemonefish, schools of rainbow runners, bluefin trevallies, neon fusiliers, and yellowback fusiliers provided a perfect farewell.
We then headed back to Kawthung for Burmese immigration, shared a last beer at the Smile Bar, and returned to Ranong, closing another unforgettable Mergui and Burma Banks adventure aboard the Smiling Seahorse.