MV Koon 9 · Richelieu Rock & Similan Islands Liveaboard

A submerged horseshoe pinnacle 200km offshore — the only true open-ocean seamount you can dive in Thailand. Every square metre is alive: violet and crimson soft corals pulsing in the current, schools of chevron barracuda spiralling overhead, harlequin shrimp tucked into crevices, tiger-tail seahorses, ghost pipefish, and tomato anemonefish guarding their hosts. From late February to early April this is one of the most reliable whale shark sites on the planet — but in December the macro hunting is at its peak, with cuttlefish hunting in pairs and rare frogfish for the patient eye. You will dive it 3–4 times in the 3D/2N format, each time discovering a different face of the rock.

An exposed underwater plateau swept by the Andaman's open-ocean current — and that current is exactly what brings the giants. Since 2014 the pinnacle has been one of the world's most consistent oceanic manta sites, with wingspans up to 5m gliding past the cleaning stations. Add grey reef sharks patrolling the edge, dog-tooth tuna in fast packs, schooling rainbow runners, and seasonal whale sharks. The site closed to non-divers in 2016 to protect the reef — you'll have it almost to yourself.

A dramatic ridge dropping along a sheer limestone wall to 40m, then opening into the blue. The west ridge is the famous manta cleaning station — hover quietly at 22m and the rays come to you. Schooling chevron barracuda hang above the corner, leopard sharks rest on the sand at dawn dives, and yellow-margin moray peer from cracks in the wall. The topography alone — overhangs, swim-throughs, dramatic drop-offs — makes this a photographer's site.

Nine granite islands forming one of the world's most photographed dive parks. Massive boulders create cathedral-like swim-throughs at sites like Elephant Head Rock and Boulder City, while the eastern reefs offer gentle hard-coral slopes alive with anthias, fusiliers and reef sharks. Hawksbill turtles cruise the bommies, octopus colour-shift across the rocks, and at North Point the visibility regularly exceeds 30m. Featured on every 3D/2N (Friday) and 4D/4N departure.

The reset between the adrenaline sites. Surin is a national marine park with some of the healthiest hard coral cover left in the Andaman — staghorn gardens, cabbage corals, and porites bommies the size of small cars. Cruising hawksbill turtles, schooling yellow snapper draped over the bommies, blue-spotted stingrays on the sand, and if you're lucky the elusive Blue Ring Angelfish that draws specialists from around the world. Perfect for relaxed exploration, photography practice, and decompressing your nitrogen between deeper Richelieu and Tachai dives.