This expedition through the Andaman Sea unfolded as a gradual exploration of both landscapes and marine life, shaped by shifting currents, encounters, and the quiet surprises hidden along the reefs. While we don't have photos for every sightings, we had some really special encounters!!! The highlight was probably a snaggletooth shark and Bowmouth guitarfish two very rare of the many sharks and rays seen this week!!!
From the dramatic limestone formations of the South Andaman to the exposed pinnacles of the North, each dive revealed a new layer of biodiversity. From the sheltered bays of Koh Phi Phi and Koh Lanta to the dynamic sites of the Similan and Surin National Parks, the week developed into a seamless blend of colourful reefs, schooling fish, and intricate macro life.
From the dramatic limestone formations of the South Andaman to the exposed pinnacles of the North, each dive revealed a new layer of biodiversity. From the sheltered bays of Koh Phi Phi and Koh Lanta to the dynamic sites of the Similan and Surin National Parks, the week developed into a seamless blend of colourful reefs, schooling fish, and intricate macro life.
Day 1 – From Phuket to Koh Phi Phi National Park
We departed this adventure from Phuket with our guests from France, the UK and the USA, setting course toward the iconic Phi Phi Islands. Known for their towering limestone cliffs and emerald waters, the islands also shelter vibrant reefs teeming with life.
Anchored beneath the cliffs for the night, the atmosphere was calm and promising — a quiet beginning before the rhythm of diving took over.
Anchored beneath the cliffs for the night, the atmosphere was calm and promising — a quiet beginning before the rhythm of diving took over.
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Day 2 – Koh Phi Phi & Koh Lanta National Park
Our check dive at Bida Nok immediately set the tone. Hypselodoris purpureomaculosa added colour to the reef alongside ghostpipefish and flounders resting on the sand. A hawksbill turtle cruised by while a group of ten blacktip reef sharks patrolled the shallows. A tigertail seahorse clung delicately to the reef, while purple urchin shrimps moved among spines.
Around them, schools of five-lined snappers, yellowback fusiliers and Moorish idols filled the water column, joined by butterflyfish, surgeonfish and parrotfish grazing the reef.
Macro life was already hinting at what was to come — a richness that would only intensify as the expedition progressed.
Around them, schools of five-lined snappers, yellowback fusiliers and Moorish idols filled the water column, joined by butterflyfish, surgeonfish and parrotfish grazing the reef.
Macro life was already hinting at what was to come — a richness that would only intensify as the expedition progressed.
 Black tip reef shark |  Hawkbill turtle |
Moving on to Koh Lanta national park, we started with a macro treasure hunt at Koh Haa Cathedral. Noumea norba, Bornella, Phyllidiopsis striata, Halgerda bacalusia (candy halgerda) and Halgerda willeyi decorated the walls, while an Anker whip coral shrimp carrying eggs hovered delicately. Coral groupers, copperband butterflyfish, Indian sailfin tang and cleaner wrasse completed the scene.
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At Hin Daeng & Hin Muang, the pace picked up with schools of rainbow runners, giant trevallies and bluefin trevallies hunting in the blue. Batfish hovered mid-water, a hawksbill turtle passed by, and ghostpipefish blended into the reef. Jellyfish drifted through the current while juvenile emperor angelfish, bentstick pipefish, juvenile brown coral blenny, peacock mantis shrimp and longnose hawkfish kept divers scanning every corner.
Schools of fusiliers, snappers and surgeonfish added constant movement.
Schools of fusiliers, snappers and surgeonfish added constant movement.
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The night dive at Hin Daeng revealed Noumea sp., Hypselodoris sp., swollen bubble snails, barred-fin moray and minor moray, along with blacktail Zanzibar urchin shrimp, skeleton shrimp, tapestry shrimp and spotted reef crabs. Around them, sleeping parrotfish, hunting lionfish and active shrimps completed the nocturnal reef.
Day 3 – Koh Tarutao National Park
At 8 Mile, visibility opened wide over the pinnacle. Bentstick pipefish hovered above the reef while redbar anthias and juvenile angelfish filled the water column. Fimbriated morays peered from crevices as Spanish mackerel and great barracuda cruised past. The unusual half grouper–half barramundi added a curious highlight (same one as last trip).
Schools of fusiliers, surgeonfish and snappers moved constantly in the current.
Schools of fusiliers, surgeonfish and snappers moved constantly in the current.
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Stonehenge brought a quieter atmosphere with a seahorse, Phestilla melanobrachia and flounders resting on the sand, surrounded by wrasses, damsels and butterflyfish moving between soft corals.
At Koh Taru, schools of five-lined snappers dominated the reef, joined by Phestilla melanobrachia and tiger cowries. Fusiliers, goatfish and sweetlips added movement as the light softened toward sunset.
At Koh Taru, schools of five-lined snappers dominated the reef, joined by Phestilla melanobrachia and tiger cowries. Fusiliers, goatfish and sweetlips added movement as the light softened toward sunset.
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Day 4 – Koh Lanta National Park
Hin Daeng & Hin Muang once again delivered strong currents and active reefs, with schools of trevallies, fusiliers and snappers swirling around the pinnacles, alongside batfish, ghost pipefish, surgeonfish and reef predators patrolling the blue.
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At Koh Haa Chimney, the dive shifted back to macro life with Halgerda bacalusia, Cuthona sibogae, Risbecia pulchella and ghostpipefish. Inside the structure, glassfish shimmered while outside, sweetlips, groupers, parrotfish and angelfish filled the reef.
After the dive, we began our overnight crossing toward the Similan Islands, leaving the southern reefs behind.
After the dive, we began our overnight crossing toward the Similan Islands, leaving the southern reefs behind.
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Day 5 – Similan National Park
West of Eden surprised us with a rare snaggletooth shark, alongside whitetip reef sharks cruising the reef. Pygmy pipehorse hovered delicately while McCosker’s flasher wrasse darted through the water column. The reef revealed a batwing psychedelic seaslug and a perfectly camouflaged devil scorpionfish, surrounded by butterflyfish, surgeonfish, wrasses and schools of fusiliers.
 McCosker’s flasher wrasse |  batwing psychedelic seaslug |
At Elephant Head Rock, blue ribbon eels waved from their burrows while octopus moved across the rocks. Three-spot angelfish and a young adult yellow boxfish stood out, while an Andaman jawfish guarded its eggs. Trevallies, snappers and sweetlips completed the dramatic setting.
North Point brought whitetip sharks, a Jenkins whipray and a juvenile Spanish dancer, alongside a wavy sap-sucking seaslug and a passing guitar shark. Schools of fusiliers and snappers added movement.
North Point brought whitetip sharks, a Jenkins whipray and a juvenile Spanish dancer, alongside a wavy sap-sucking seaslug and a passing guitar shark. Schools of fusiliers and snappers added movement.
 2 blue ribbon eels together |  Jenkins whipray |
At Koh Bon Ridge during sunset, a whitetip reef shark moved repeatedly in and out of the reef, patrolling close to divers in a memorable encounter.
The blackwater dive revealed spear mantis shrimp larvae, squids, pelagic snails, zoea crabs, siphonophores, “pompom tail” shrimp larvae, flatworm larvae, blenny larvae, shrimp larvae, moray eel larvae and larval anemones drifting through the dark.
Blackwater once again delivered the surreal, reminding us that some of the ocean’s most fascinating life exists far from the reef.
The blackwater dive revealed spear mantis shrimp larvae, squids, pelagic snails, zoea crabs, siphonophores, “pompom tail” shrimp larvae, flatworm larvae, blenny larvae, shrimp larvae, moray eel larvae and larval anemones drifting through the dark.
Blackwater once again delivered the surreal, reminding us that some of the ocean’s most fascinating life exists far from the reef.
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Day 6 – Similan National Park
At Koh Bon Bay, orange-spotted glassy bubbles (Hyppo snails) on the reef while a school of batfish gathered in the current alongside giant trevallies and double-spotted queenfish.
 This bowmouth was spotted at the Burma banks but as we don't have photos of this week's sighting, it will do :) |  school of golden batfish in Koh Bon pinnacle |
On Koh Bon West Ridge, an incredible encounter with a bowmouth guitar shark, alongside Spanish dancer eggs, dogtooth tuna and Spanish mackerel hunting in the blue, while fusiliers and surgeonfish filled the reef.
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Koh Bon Pinnacle was alive with schools of batfish, clown triggerfish, bluefin trevallies, barracudas and yellowback fusiliers.
At Koh Tachai Pinnacle, large schools of barracudas, batfish, giant trevallies, bluefin trevallies and bigeye trevallies dominated the dive, joined by marble groupers and painted spiny lobsters hiding in the rocks.
At Koh Tachai Pinnacle, large schools of barracudas, batfish, giant trevallies, bluefin trevallies and bigeye trevallies dominated the dive, joined by marble groupers and painted spiny lobsters hiding in the rocks.
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The night dive at Koh Tachai Reef brought hunting behaviour, with schools of checkered snappers and barracudas using our lights to hunt, while giant moray eels swam freely and blacktip sharks cruised the reef.
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Day 7 – Surin National Park (Richelieu Rock)
Four dives at Richelieu Rock delivered a spectacular finale. White and yellow ornate ghostpipefish hovered delicately while peacock mantis shrimp and tigertail seahorses added macro highlights.
 Ghost pipefish |  |
Schools of amber jacks, bigeye jacks, longnose emperors, giant trevallies, bluefin trevallies and rainbow runners filled the blue, while juvenile bridled monocle bream, baby octopus, Spanish mackerel and juvenile clown triggerfish added variety. Female Moyer’s dragonet and male Morison’s dragonet completed the scene.
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Nudibranch diversity was exceptional, including Risbecia pulchella, Chromodoris geometrica, Glossodoris atromarginata, Hypselodoris bullocki, bicolor flabellina, Gymnodoris nigricolor and Glossodoris pallida, while flatworms such as Pseudobiceros sp7 added even more colour.
Around them, dense schools of fusiliers, snappers and glassfish wrapped the pinnacle in constant motion.
Around them, dense schools of fusiliers, snappers and glassfish wrapped the pinnacle in constant motion.
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Day 8 – Similan National Park & Khao Lak Coast
Our final dives brought us back to Koh Tachai Pinnacle, where a hawksbill turtle, schools of batfish, bigeye jacks, barracudas and Spanish mackerel closed the trip with strong pelagic action.
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At Boonsung Wreck, a completely different atmosphere awaited. Blue-spotted Kuhl’s rays rested on the sand, honeycomb morays hid within the structure and bentstick pipefish hovered nearby. Schools of fusiliers, snappers, sweetlips and trevallies turned the wreck into a true fish haven.
 Bent stick pipefish |  honeycomb moray eel |
We then returned to Tap Lamu Pier in Khao Lak, saying goodbye after another rich and diverse journey through the Andaman Sea.
From limestone reefs to offshore pinnacles, this journey captured the changing rhythm of the Andaman Sea — where each dive revealed a new balance between movement, colour and hidden detail.
Until the next tide brings us together again — dive well, dive aware, and see you soon, fellow divers.
From limestone reefs to offshore pinnacles, this journey captured the changing rhythm of the Andaman Sea — where each dive revealed a new balance between movement, colour and hidden detail.
Until the next tide brings us together again — dive well, dive aware, and see you soon, fellow divers.
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