Scuba diving & snorkelling in Thailand: the rules, the park fees, the seasons and what it costs.

The rules changed on 22 April 2025 — and they bind you, not just the boat

This is the part most diving guides still have not updated. The Announcement on the Protection of Coral Resources from Diving Tourism Activities B.E. 2568 was published in the Royal Gazette on 22 April 2025, took effect immediately and runs for five years. It is national in scope, it is made under the Marine and Coastal Resources Management Act, and both the Tourism Authority of Thailand and the government portal at thailand.go.th publish the same set of requirements. Practically, it changes what a legitimate operator will let you do.

• A supervisor on every trip. Every excursion has to be accompanied by a certified dive supervisor or assistant supervisor, and they must brief you on the applicable law before you get in.
• Two metres above the coral. Divers are required to keep at least two metres of clearance above coral heads. No touching or handling marine life, no feeding fish, no littering, and no kicking up sediment through sloppy fin control.
• Life vests for snorkellers near reefs, unless you hold a recognised freediving certificate.
• No camera below Advanced or 40 dives. Photography is not permitted during training dives unless the person holding the camera has an Advanced Open Water certification from PADI, SSI or an equivalent agency, or has logged at least 40 dives — and operators are told not to hand cameras to unqualified divers on recreational dives either.
• Underwater walking tours, including Sea Walker, are banned in coral zones.

Two coasts, two dive seasons

Thailand straddles two seas, and that single fact governs almost everything about diving here. The Andaman Sea on the west — Phuket, Krabi, Khao Lak, the Similan and Surin Islands — has the clearest water and the marquee sites, but it is exposed to the southwest monsoon, and its marine parks physically close for roughly five months a year. The Gulf of Thailand on the east — Koh Tao, Koh Phangan, Koh Samui, Pattaya and Sattahip — is calmer, cheaper and diveable year-round, which is why it is where almost everyone learns. Read the seasons and you can dive somewhere good in Thailand in any month; our weather and seasons guide maps the wet and dry windows coast by coast, and the monsoon guide covers what the southwest monsoon actually does on land.

If you are choosing a base rather than a holiday, that seasonal split is the whole decision: Phuket and Krabi put the best diving in Thailand within reach for half the year, while a Gulf base trades the headline sites for the ability to dive every weekend. Our best cities for scuba diving page compares them, and compare Thai cities puts the cost of living beside it.

National park fees: there is no single rate, and the dive parks are the expensive ones

Almost every dive site worth travelling for in Thailand sits inside a marine national park, so the park fee is part of the price of the dive. The Department of National Parks sets it by band, not by park, under a regulation published in the Royal Gazette on 9 December 2021 and in force since 7 June 2022. A “child” is 3 to 14 years old or under 140 cm; a “foreigner” is anyone without Thai nationality, whether or not they live here.

Then there is a layer most people never hear about until the boat asks for more money. A separate departmental announcement dated 19 September 2022, made with the approval of the National Park Committee at its meeting of 9 September 2022, designates certain sites as requiring a special service fee above their park’s normal band. Two of them matter enormously to divers:

• Hin Daeng and Hin Muang, plus Koh Rok, Koh Ha and Koh Ngai, in Mu Ko Lanta National Park — 400 baht foreign adult, 200 child. Double the 200 the rest of that park charges, and the reason a day trip to the pinnacles costs more than a day trip to the reefs.
• Koh Wua Talap and Koh Mae Koh in Mu Ko Ang Thong — 300 baht foreign adult, 150 child.

The Similans are day-trip only — and the liveaboard fleet is a written exception

People assume the liveaboards exist because the islands are far away. The real reason is a legal one, and it is worth knowing because it explains the shape of the whole Andaman dive market.

An announcement signed by the Director-General of the Department of National Parks on 4 October 2018 and published in the Royal Gazette on 8 October 2018 closed overnight accommodation in Mu Ko Similan National Park outright, converting tourism there to a day-return model. The stated reason was blunt: deterioration and damage to coral, marine life and the ecosystem caused by wastewater from overnight tourism. It was made under clauses 4(7) and 5 of the department’s 2009 regulation on entry into national parks, and took effect the day after publication.

The announcement contains exactly one exemption: persons licensed to provide tourist services within the national park in the scuba diving category. That is the liveaboards. A dive boat lying at anchor off Koh Similan overnight is not evading the rule — it is the named carve-out from it, and it is why you cannot book a beach bungalow on the Similans but can sleep two hundred metres offshore.

A dive site can be closed while the park is open

Seasonal closure is the predictable kind. The other kind is a bleaching closure, and it arrives with days of notice and can last a year.

Hat Noppharat Thara–Mu Ko Phi Phi National Park closed a group of snorkelling and scuba sites on 13 May 2024 after coral bleaching was found — warm water causing corals to expel the zooxanthellae that give them their colour. They stayed shut for roughly eleven months. On 17 April 2025 the park chief reopened ten of them: the northern and eastern sides of Koh Gai, the northern side of Koh Poda and Ao Pu Ya on it, Koh Daeng, Railay Bay, Koh Yawasam, Loh Ba Gao Bay, Viking Cave and the front of Pi Leh Bay — while the western side of Koh Gai at Ao Khang Khao stayed closed to protect a more fragile stretch of reef.

The practical lesson is that a dive shop’s printed site map is a wish list, not a permission list. Individual parks issue and cancel these orders themselves, and the same coral protection announcement that governs your buoyancy also gives the authorities the basis to shut a site. Ask on the day what is actually open, and treat an operator who promises a specific bleached-out site as a warning sign rather than a good deal.

Getting certified: two Koh Tao rate cards, read on the day

To dive beyond a supervised shallow taster you need an Open Water certification from PADI, SSI or an equivalent agency — a lifelong qualification, not a local permit. Koh Tao in the Gulf is where most people in Asia get it: sheltered bays, warm shallow water and dozens of schools competing on a small island. Rather than quote a range, here are two schools’ own published cards, read on 6 September 2026. They are examples of the market, not recommendations, and prices change.

All figures in baht. Both include equipment rental, certification fees and digital materials in the course price; Isla Tortuga bundles insurance into its fun-dive packages, Black Turtle prices accommodation separately and takes a deposit. Both publish a Sail Rock day trip at 3,200 baht for two dives — the pinnacle between Koh Tao and Koh Phangan is the region’s signature site and is priced as a separate excursion, not as an ordinary fun dive. Black Turtle also publishes a combined Open Water plus Advanced package at 23,650, and Isla Tortuga a Rescue Diver at 14,000 with EFR first aid or 10,000 without.

The spread between those two cards is about 3,000 baht on the same certification, which is the honest answer to “how much does it cost”. What separates them is class size, gear age and whether accommodation is thrown in — and, since April 2025, whether the school runs the legally required one instructor to four students on a certification course. That ratio is now a rule, so it is a fair question to ask before you pay a deposit.

Where the chambers are — and where they are not

Decompression illness is rare and time-critical, and Thailand’s chamber coverage is thinner than most divers assume. Hyperbaric Services of Thailand, operating as the SSS chamber network, lists three Thai locations on its own network page: Phuket, Khao Lak and Koh Tao.

The Phuket unit opened in 1996 and is the substantial one: a multiplace chamber taking up to four occupants including the inside attendant, pressurising to 50 metres (165 feet), which is deep enough to run the full US Navy treatment tables for decompression sickness and arterial gas embolism.

Dive cover and a resident health plan are different products solving different problems — our health insurance in Thailand guide explains how they sit together.

Snorkelling — no certification, but the rules still apply to you

You need no qualification to snorkel, and Thailand is generous with it: the reefs off Koh Phi Phi, the Surin Islands, Koh Lipe, the Racha Islands and dozens of day-trip stops are shallow and easy. What changed in April 2025 is that snorkelling is explicitly covered by the coral protection announcement, not just scuba. Near reefs you are required to wear a life vest unless you hold a freediving certificate; the operator must have a supervisor for every twenty of you; and standing on, touching or kicking coral is prohibited for a snorkeller exactly as it is for a diver. The vest is not only a safety device — it keeps you off the reef by keeping you on the surface, which is the point.

If you are picking a coast to live on rather than visit, beaches and water safety covers rip currents, jellyfish and flag systems, and island living in Thailand covers what a year on one is actually like. For getting to the dive coasts, see the airport guide and domestic flights.

What we could not confirm

Written down so you can see the edges of this page rather than guess at them.

• The penalty for breaching the diving rules. Thai PBS Policy Watch reports it as imprisonment not exceeding two years, a fine not exceeding 200,000 baht, or both, under section 29 of the Marine and Coastal Resources Management Promotion Act B.E. 2558, and reports the measure as covering 17 provinces and about 149,182 rai of reef. Neither the TAT nor the thailand.go.th page states a monetary penalty or a province count, and we could not open the Act text, so those figures are reported rather than confirmed here.
• The Royal Gazette PDF of the 2018 Similan overnight closure returned a 403 to automated retrieval. Its text is quoted from the Gazette’s indexed record, and the volume, part, page, signing date and Director-General are given above so it can be checked by hand.
• The 200-baht-per-day liveaboard park surcharge could not be matched to a departmental fee schedule, and operators publish conflicting structures.
• The 2026 Similan and Surin closure dates differ between ONEP, the Government Public Relations Department and the department’s own reservation page, as set out above. No single date is printed here as authoritative.
• The contents of the January 2026 dive supervisor card regulation — qualifying route, testing, validity and any transition period — are not summarised because we could only reach the DMCR listing, not the regulation PDF.
• Whether a dive instructor or divemaster role sits on Thailand’s restricted-occupation schedule. The general rule that paid work requires a work permit is stated; the specific occupational listing is not, because we could not confirm it.
• A current, consolidated list of closed dive sites. Individual parks issue these orders themselves and there is no single national register we could locate, which is exactly why the page says to ask on the day.
• No dive operator on this page is recommended. Two Koh Tao schools are named solely because they publish a full price list; that is a sourcing decision, not an endorsement.

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