The Mergui Archipelago — some 800 islands scattered across Myanmar's slice of the Andaman Sea — is the wildest, least-dived corner of the region you can still reach by liveaboard from Phuket. Far fewer boats run here than to the Similans, the reefs see almost no day-trip traffic, and the headline sites like Black Rock and Western Rocky deliver big-animal encounters in genuine wilderness. This guide covers when to go, what you'll dive, the level you need, the Myanmar government fee that catches first-timers out, and realistic prices.
Where Mergui is and why it's special
The Mergui (or Myeik) Archipelago lies north of Thailand's Similan and Surin islands, in Myanmar waters. Boats clear out of Thailand near Ranong, cross into Burma, and spend several days diving sites that most divers never reach. Because the area only reopened to foreign liveaboards in recent decades and access is tightly controlled, the reefs are remarkably intact and the topside scenery — uninhabited jungle islands, empty white beaches, the occasional Moken sea-gypsy village — is unlike anywhere else in the Andaman.
This is expedition diving rather than a relaxed reef holiday. Sites are spread out, currents can be strong, and visibility is variable — you trade the polish of a Similan trip for solitude, sharks, and the feeling of dropping onto reefs that simply aren't crowded. For experienced divers, that's exactly the appeal.
Best season for a Mergui liveaboard
The wider Andaman liveaboard season runs roughly from 15 October to 15 May, when the northeast monsoon brings calm seas. Mergui trips sit at the heart of that window: most operators run Burma itineraries from November through May, and the prime months are February to May.
That late-season sweet spot is no accident. Black Rock and Western Rocky — the two signature Mergui sites — fish best from February to May, and the plankton blooms that bring whale sharks and manta rays peak roughly February to April. If sightings of the big pelagics are your goal, aim for that core period. Outside the season, from mid-May into October, the southwest monsoon makes the crossing rough and most boats stand down.
Signature dive sites
Black Rock is the crown jewel: a lone pinnacle rising from deep water, with a wall dropping well past 100 m and dive profiles typically in the 5–40 m range. It's an advanced site known for manta rays, occasional whale sharks, grey reef sharks and schooling fish — best dived from February to May.
Western Rocky is a cluster of rocks famous for a swim-through cave that often shelters nurse sharks, plus macro life on the surrounding reef. Depths run from about 5 to 30 m and it suits intermediate-to-advanced divers; best months are February to May.
Many Burma itineraries also include or combine Richelieu Rock, the legendary horseshoe-shaped pinnacle on the Thai side near the Surin Islands. With depths from 5 to 35 m and a recommended level of intermediate to advanced, it's one of the Andaman's richest sites and fishes best from February to April — a natural bookend to a Mergui crossing.
What level and certification you need
Mergui is not a place to log your first open-water dives. The flagship sites are graded intermediate-to-advanced or advanced, currents can run hard, and many of the best moments happen below 18 m. As a practical minimum, plan on an Advanced Open Water certification (or equivalent) and a solid number of logged dives before you commit to a Burma expedition.
Nitrox is strongly recommended for the deeper, repetitive diving — it extends your no-decompression limits and adds a margin of safety across a packed daily schedule. If you're newer, build experience on a Similan or Surin trip first, then step up to Mergui. Non-divers and snorkellers can sometimes join depending on the boat, but the itinerary is built around serious diving.
The Myanmar permit and government fee
This is the part first-timers miss. Diving in Myanmar waters requires official permits, and Myanmar levies a mandatory per-person government and permit fee on top of the trip price. It is not optional and not something an operator can waive — it's the price of access to a tightly regulated marine area.
As a realistic retail guide, budget on the order of US$250–450 per person for the combined permit and government charges, depending on the operator and the length of the itinerary. Always confirm the exact figure and what it covers when you book, and check passport-validity and any current entry requirements well ahead of departure, as Myanmar's rules can change at short notice.
How much a Mergui trip costs
Mergui is a premium product because trips are longer, run further, and carry the added permit costs. As a realistic retail guide, a multi-day Burma expedition typically lands somewhere between about THB 48,000 and THB 130,000+ per person — roughly US$1,400 to US$3,800+ — depending on the vessel's comfort level, cabin type, trip length and season.
Smaller, more luxurious boats sit at the top of that range, while well-run mid-range vessels offer the same access for less. On top of the fare you'll add the Myanmar permit fee, marine-park and port charges, equipment rental if needed, Nitrox where it isn't included, and crew tips. We'll quote you a clear all-in retail figure for the specific dates and boat you're considering.
Choosing the right boat
Not every liveaboard runs Burma — the crossing and permits mean it's a specialist itinerary. Look for boats with a proven Mergui track record, comfortable cabins for the longer trip, and a dive deck set up for deeper, current-prone diving with Nitrox available.
Tell us your certification level, how many dives you've logged, your dates and your budget, and we'll match you to a vessel that actually runs the Mergui route in your window — then handle the permits, transfers from Phuket or Ranong, and the full quote.
Featured vessels for this trip
Frequently asked questions
When is the best time for a Mergui liveaboard?
The Andaman season runs roughly 15 October to 15 May, and most Burma trips operate November through May. The prime window is February to May, with whale sharks and manta rays most likely from February to April.
Do I need a special permit or fee for Burma / Mergui?
Yes. Diving in Myanmar waters requires official permits, and there is a mandatory per-person government and permit fee on top of the trip price — realistically on the order of US$250–450 per person, depending on the operator and itinerary length. Confirm the exact amount when you book.
What certification level do I need for Mergui?
It's an intermediate-to-advanced destination. Plan on an Advanced Open Water certification (or equivalent) and a good number of logged dives. Strong currents and depths beyond 18 m are common, and Nitrox is strongly recommended.
What are the must-dive sites?
Black Rock (an advanced pinnacle with a 100 m+ wall and mantas, best Feb–May) and Western Rocky (a famous cave swim-through with nurse sharks, 5–30 m, best Feb–May). Many trips also combine Richelieu Rock on the Thai side, best Feb–April.
How much does a Mergui liveaboard cost?
As a retail guide, a multi-day Burma expedition runs roughly THB 48,000 to 130,000+ per person (about US$1,400–3,800+), plus the Myanmar permit fee, marine-park and port charges, gear rental, Nitrox where extra, and tips. We'll quote an all-in figure for your dates and boat.
Can non-divers or snorkellers join a Mergui trip?
Sometimes, depending on the boat, but Mergui itineraries are built around serious diving and long crossings. If you have non-diving guests, tell us up front so we can recommend a vessel that suits the whole group.