Some links are affiliate links, read our disclosure ↗ Destinations · July 2026 · Field journal
NOMADREEFfield journal The dispatch
Destinations · Researched guide

Phuket Diving: 8 Assessed Operators, and the Five Months the Similans Are Shut

Yannick Schrothby Yannick Schroth Aug 15, 2026 5 min read
Granite boulders and clear water at Donald Duck Bay in the Similan Islands, Thailand

Photo: No Troubles Just Bubbles, Wikimedia Commons, CC BY-SA 4.0.

Phuket carries 8 operators in the Green Fins register and every one has been assessed in person within the last twelve months. The thing to settle before booking anything is the calendar: the Similan Islands, where a great many Phuket dive trips actually go, are closed by the national park authority for about five months a year, and a booking that ignores that is a booking for somewhere else.
Reefs, rules and operators all change. Confirm the current picture before you book.
How this guide was made, and what it is not. Nobody from NOMADREEF has dived Phuket. This is not a trip report and it contains no first-hand observation, because inventing one would be worth less to you than saying so. It is built from sources you can open yourself, listed at the foot, and from our own reading of the Green Fins member register on 2026-08-14, which is the part you will not find elsewhere. Where a fact could not be confirmed at its primary source, it is marked as unconfirmed rather than repeated.

Key takeaways

The closure is the first thing to check

The Tourism Authority of Thailand's own listing of park status gives Mu Ko Similan National Park as “Closed from 16 May until 14 October”, and adds that Ko Ta Chai, the island, beach and reef, is “Closed until further notice”. That listing carries a last-updated date of 7 July 2023.

Reporting on the 2026 season gives the closure as 15 May to 15 October, one day different at each end. We are not going to pretend to resolve that. Treat the closure as mid-May to mid-October and confirm the exact dates for your year with the Department of National Parks or with the operator taking you. The department's own portal carried no closure announcement on the day we looked, which is why the tourism authority is cited here rather than the park authority itself.

What is not in doubt is the shape of it: for roughly five months a year the best-known diving reached from Phuket is unavailable, and a page that sells you a Similan trip without saying so is not being straight with you.

What the register shows

Green Fins is run by the Reef-World Foundation with the UN Environment Programme, and its assessments are made in person by trained assessors rather than by self-declaration. On 2026-08-14 the register carried 8 members in Phuket: 1 Gold, 4 Silver and 3 Bronze.

All 8 carry an assessment marked in person within the last 12 months. That completeness is worth more than the tier itself: it means the rating describes the business as it operates now rather than at some unstated point in the past. Every name and the evidence behind each field is on the Phuket operator list.

What the operators say about themselves

Separately from the register we opened each operator's own site; 8 of the 8 responded. Training agencies they name themselves, which is their claim and not a check by anyone: PADI on 3 and SSI on 1. Fewer than half name any agency at all, which is lower than most places we have compiled, and it is a gap rather than a verdict.

Not one of the 8 publishes which languages their instructors teach in. A dive briefing is a safety briefing, so this is not a comfort question.

What we did not verify

Park entry fees, boat prices, liveaboard schedules, transfer times and monsoon risk windows are hard facts under our rules and we did not confirm them at a primary source for this location. They are absent rather than guessed at. The park authority and the operator you book are the places to ask.

Questions

When are the Similan Islands closed?

Roughly mid-May to mid-October each year. The Tourism Authority of Thailand's park listing says 16 May to 14 October and was last updated 7 July 2023; reporting for 2026 gives 15 May to 15 October. Confirm the current year with the Department of National Parks.

How many Phuket operators are independently assessed?

All 8 in the Green Fins register carry an in-person assessment from the last twelve months. The spread is 1 Gold, 4 Silver and 3 Bronze.

Are the Similans in Phuket?

No. They are a separate national park reached from Phuket by day trip or liveaboard, which is why the closure changes what a Phuket dive week can contain.

Yannick Schroth
Yannick Schroth

Writes NOMADREEF and compiles its operator directory. This guide is desk research, not a trip report, and says so at the top. About the author

What this guide is, and is not. This is independent research by the operator of this site, not reviewed by a lawyer and not medical or safety advice. Listing an operator is not a safety endorsement: we have not dived with these businesses, inspected their equipment or watched a briefing. Diving carries risk that no register removes. Every fact here carries the date we checked it, and anything we could not confirm is marked as unconfirmed rather than smoothed over. Confirm what matters before you book.

Sources

  1. Tourism Authority of Thailand, opening and closing status of Thailand's national parks, last updated 7 July 2023. Closure dates for Mu Ko Similan National Park, read 2026-08-14.
  2. Department of National Parks, Wildlife and Plant Conservation, portal.dnp.go.th. Checked 2026-08-14 for a current closure announcement; the portal carried none, which is why the tourism authority is cited above.
  3. Green Fins member register, Reef-World Foundation with the UN Environment Programme, greenfins.net. Membership levels and assessment status for 8 operators, read 2026-08-14.
  4. Each operator's own website, opened 2026-08-14, for the training agencies they name. Recorded on our operator list.
← All destinations