Trip report: Mergui Archipelago & Burma Banks 14th – 21st December 2025

Day 1 – From Ranong to the Mergui Archipelago

​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.

Day 2 – South & North Twin Reefs
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​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.

Day 3 – Black Rock
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​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.

Day 4 – Three Islets & Sailing to the Burma Banks
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​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.

Day 5 – Burma Banks
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​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.

Yellow sea snails eating a yellow cup coral to replace it with its eggs. Egg mass visible on the lower right corner.

Day 6 – Burma Banks next

​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.

Day 7 – Sea Fan Forest & Western Rocky
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​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.

Day 8 – Dendro’s Peak & Farewell
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​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.