Getting to the Mergui Archipelago means committing properly — there are no casual day trips here. The only practical way in is via liveaboard, typically departing from Kawthaung in Myanmar's far south or crossing from Ranong in Thailand. A handful of operators run these routes, with trip lengths usually sitting between seven and twelve nights.
Budget and mid-range options exist, but vessel quality varies considerably, so it pays to research the boat rather than just the itinerary.
What you find underwater justifies the effort. Visibility regularly reaches 20–25 metres across the outer islands, and currents are generally mild, making this accessible for Open Water divers willing to handle the remoteness. Depths worth exploring sit between 5 and 30 metres — shallow enough for snorkellers on the calmer sites, with wall dives and swim-throughs rewarding those who go deeper.
I've watched leopard sharks resting on sandy patches at around 18 metres without a single other diver nearby, which feels almost absurd compared to busier Indo-Pacific destinations. Seahorses, ghost pipefish, and reasonably dense soft coral growth appear throughout, and schooling barracuda are common on the channel sites.
Reef condition is genuinely encouraging relative to regional averages. Lower visitor pressure has spared many sites from anchor damage and physical contact stress, though bleaching events have touched the shallower sections during warm years. The Moken communities you'll pass between dives add real cultural weight to the experience — these are not performances for tourists.
The northeast monsoon clears between November and April, making that the reliable dive window; Open Water certification is sufficient for most sites, but comfort in mild current and open-ocean conditions is assumed.