Liveaboard Diving in Thailand

The Andaman Sea has a strict season: liveaboards run from mid-October to mid-May, with the marine parks closed entirely from mid-May to mid-October due to the southwest monsoon. Within the open season, October to December is wet shoulder with occasional storms but excellent visibility and fewer crowds. January to April is the dry, calm peak — water 28-29°C, visibility 25-35 m, manta and whale shark season at Koh Bon, Koh Tachai and Richelieu Rock peaking February to April. May is the closing month, typically still excellent diving but with the chance of storms returning. The Mergui Archipelago in Myanmar shares the same season but offers fewer boats and more remote sites. For Koh Tao and the Gulf of Thailand (a separate destination, mostly day-boat) the calendar is reversed: best diving June to September.

Phuket International Airport (HKT) is the main entry point, served by direct flights from across Asia, the Middle East and a growing number of European cities (especially in winter). Most liveaboards embark from Tap Lamu pier in Khao Lak, a 60-90 minute drive north of Phuket airport — transfers are usually included or available for a small fee. A handful of itineraries depart from Chalong pier on Phuket itself. Visa-free entry is 60 days for most Western nationalities. Mergui (Myanmar) trips often start in Ranong (UNN) — a domestic flight from Bangkok or a long road transfer — and require a separate Myanmar entry permit handled by the operator. Build a buffer night in Phuket or Khao Lak; flight delays are uncommon but the drive to Tap Lamu is a working road.

Tap Lamu pier (Khao Lak) is the principal embarkation point for Similan, Surin, Richelieu Rock and combination itineraries. Chalong pier (Phuket) serves a few liveaboards and most day-boat operators. Ranong is the gateway to the Mergui (Burma) Archipelago. All three ports have basic refueling, customs and immigration; Tap Lamu is the most diving-focused with several dive shop offices and a small commercial strip.

The Similan Islands form a string of nine granite islands famous for their underwater boulder formations and clear blue water — sites like Elephant Head Rock, East of Eden and West of Eden offer swim-throughs, soft coral and reliable reef life. Koh Bon and Koh Tachai, north of the Similans, are the manta hotspots — gentle giants visit cleaning stations from January to May, sometimes with multiple animals at a single dive. Richelieu Rock — a horseshoe-shaped pinnacle off the Surin Islands — is Thailand's signature site, blanketed in purple soft coral and famous for whale shark encounters in the spring. The Surin Islands themselves offer some of Thailand's best hard coral. Hin Daeng and Hin Muang in the south (often combined with Phi Phi and Koh Lanta in southern itineraries) deliver dramatic walls, soft coral and frequent manta and whale shark sightings. The Mergui Archipelago in Myanmar offers untouched coral, the Burma Banks (deep seamounts with shark action) and an empty, frontier feel.

Thai liveaboards are excellent value — typical prices are 30-50% lower than Maldives or Indonesia for similar quality, especially on shorter 3-5 night trips. Tipping is appreciated though slightly less obligatory than in some destinations: $80-150 per guest per week is generous. Thai baht is the local currency but USD and EUR are accepted by most operators for the trip itself. Bring small THB bills for park fees (around $30 per dive day, paid on board), bar tabs and souvenirs. Water is warm (28-30°C) so a 3 mm full wetsuit or even a shorty is enough. Nitrox is widely available, usually $80-120 per week. Thai cuisine on board is universally praised — a real highlight of the experience. Power outlets are typically a mix of American flat-pin and European round-pin; bring a universal adapter.

Thailand requires Advanced Open Water for most liveaboards; a minimum of 30-50 logged dives is typical. Currents on the open-water sites (Koh Bon, Koh Tachai, Richelieu) can be moderate to strong but most diving is relaxed. Hyperbaric chambers are available in Phuket (multiple) and Bangkok. Wi-Fi is available on most modern liveaboards (sometimes free, sometimes paid). Domestic alcohol is cheap and available on all boats; bar tabs are settled in cash or by card at the end. The Similan and Surin marine parks have entry restrictions — only licensed operators can enter, and certain camping islands are sometimes closed for restoration. Thai liveaboards are typically smaller (8-22 guests) than the larger Phinisi-style boats of Indonesia.

The Andaman season is short and weather windows can vary at the start (October-November) and end (May) of each season — flexible dates help. Park fees and conservation surcharges add $80-150 per guest above the headline price. The Similans can get crowded on shorter trips (2-4 night options that compete with day boats); if you want fewer divers, choose a 7+ night Surin/Richelieu/Mergui combination that keeps you north and away from the day-boat traffic. Thailand is generally very safe for tourists; standard precautions in Phuket nightlife districts apply. Mergui (Myanmar) trips have their own permit and political-risk considerations — confirm with your operator that all current paperwork is in order.