Photo: KOSIN SUKHUM, CC BY-SA 4.0, Wikimedia Commons
The Similan Islands are a national park 60 km off the coast north of Phuket, and the single most important thing to know is that they are open only from 15 October to 15 May — closed the rest of the year so the reefs recover. In season, a day trip leaves Thap Lamu pier at 8:30 and gets you back to your Phuket hotel around 18:30; a two-dive day costs ฿4,900 per person plus a ฿700 national park fee paid in cash. Diving requires certification; snorkelling does not, but it is a different boat. Here is how to plan the day.
When the Similans are open
The park season runs 15 October to 15 May. Outside it the islands are closed to visitors entirely — no boats, no exceptions, and no operator can get you there. The exact opening and closing dates are announced each year by the park authority and can shift by a few days with the weather, so if your trip falls in the first or last week of the window, book with that in mind and confirm the date.
Within the season, the water is clearest and the sea calmest from December to April. October and early November are the least predictable — the park is technically open but the tail of the rainy season still produces cancellation days.
How to get there
The Similans are reached from Thap Lamu pier in Phang Nga province, not from Phuket itself — the boat crossing is about 90 minutes. That is why a Similan day starts so early: hotel pickup on Phuket runs between 06:00 and 06:30 from Patong, Karon and Kata, the speedboat leaves Thap Lamu at 08:30, and you are dropped back at your hotel around 18:30. From south Khao Lak, which is much closer, pickup is at 07:45.
Transfers from those zones are included in the tour price, so you do not need to arrange your own way to the pier. There is no need to stay in Khao Lak to do this trip, though it does buy you an extra hour of sleep.
Diving or snorkelling — the honest difference
This is the question that decides which boat you book, and it is not about preference: the diving trip requires a certification. Our Similan Islands diving day trip is two certified dives at ฿4,900 per person, run by Sunrise Divers, an operator based on Karon since long before the day-trip boom (4.8 from 122 reviews). Breakfast, lunch and soft drinks are on board, and the group is capped at 20.
If you are not certified, the Similans are still open to you on a snorkelling day trip — a different boat, a different schedule, and a cheaper one: a Similan snorkelling day trip starts at ฿3,490 per person with the marine park fee already included, and the shared market runs up to about ฿4,100. Snorkelling trips count as boat tours rather than diving, so they sit on the Phuket boat tours page. No certification is needed, and no, you cannot join a dive boat to snorkel from it.
Compare the two honestly and the numbers invert. Snorkelling boats leave from Khao Lak, not from Phuket: a Phuket hotel pickup is a ฿400 surcharge with 97–120 minutes on the road each way (109 minutes from Patong, 120 from Kata), and the early departures collect you around 05:00. The dive trip leaves from the same pier but carries the Phuket transfer in its price. All-in from a Phuket hotel that is roughly ฿3,890–4,500 for snorkelling against ฿6,000–7,000 for two dives. Above about ฿4,300 the shared-boat market ends: there is no premium snorkelling tier here, only private charters quoted on request.
What you actually see
On Monday, Tuesday and Thursday to Saturday the dives are in the Similan Islands themselves — granite boulder formations, hard-coral gardens and the visibility the park is famous for. On Sunday and Wednesday the boat runs to Koh Bon instead, the site known for manta ray sightings. Nobody can promise you a manta; it is wildlife, and the honest answer is that the odds are better there than anywhere else nearby.
What the day costs
| Item | Cost | Notes |
|---|---|---|
| Two-dive day trip | ฿4,900/person | includes transfers, breakfast, lunch, soft drinks |
| National park fee | ฿700 | cash, collected on the day — not in the price |
| Equipment rental | ฿150–500 per item | only if you do not bring your own |
| Private guide | ฿2,000/day | optional, on request |
So a realistic all-in budget for a certified diver with rental gear is roughly ฿6,000–7,000 for the day. There are no other charges — the operator is explicit about that, which is worth more than a lower headline price with fees bolted on later.
Similans or Phi Phi — which day trip?
Different products, not competitors. The Similans are about water quality and diving: better visibility, better reefs, a longer day and a hard seasonal window. Phi Phi is about scenery and swimming, runs year-round, and works for any level — see the group speedboat tour at ฿3,900 or the premium sunrise trip from ฿5,310. If you are certified and travelling between December and April, the Similans are the better dive day in Thailand. If you are not, or the park is closed, Phi Phi and Phang Nga Bay are the answer.
Practical notes
Bring ฿700 in cash for the park fee — it is collected on the day and there is no card terminal on the water. The day is long: 12 hours door to door, most of it outdoors, so bring reef-safe sun protection and expect to be tired. Book early for the opening weeks in October and for the December–April peak — boat capacity into the park is limited by permit, not by demand. All the alternatives, in season and out, are on the Phuket boat tours page and the Phuket diving page.
If the park is closed, or you are not certified
Outside 15 October – 15 May the alternatives run year-round: Phi Phi from Phuket for beaches and snorkelling, and the wider picture is in our what-to-see-in-Phuket guide.
Booking
Tell us your dates in WhatsApp and whether you are certified — that one answer decides which boat you need. We book direct with the operator, at their price, and the opening weeks in October fill early.
FAQ
When do the Similan Islands open?
The Similan Islands National Park is open from 15 October to 15 May and closed the rest of the year for reef recovery. Exact dates are set annually by the park authority and can move by a few days.
How much does a Similan day trip cost?
A two-dive day trip costs ฿4,900 per person, plus the ฿700 national park fee in cash and ฿150–500 per item for equipment rental if needed. Transfers, breakfast and lunch are included. Budget about ฿6,000–7,000 all-in.
Do I need a diving certificate for the Similans?
Yes for the diving trip — it is two certified dives. Snorkelling the Similans needs no certificate, but it is a separate boat with its own schedule. You cannot snorkel from the dive boat.
Where do Similan boats leave from?
From Thap Lamu pier in Phang Nga, north of Phuket, at 08:30 — about 90 minutes by speedboat to the park. Hotel pickup on Phuket is included and starts at 06:00–06:30; from south Khao Lak at 07:45.
How long is a Similan day trip?
About 12 hours door to door: pickup at 06:00–06:30 on Phuket, departure from Thap Lamu at 08:30, two dives with lunch on board, and hotel drop-off around 18:30.
Can you see manta rays at the Similans?
Koh Bon, visited on Sundays and Wednesdays, is the site known for manta sightings. No operator can guarantee an encounter — it is wildlife. On other days the boat dives the Similan Islands themselves.
What is the best month to visit the Similans?
December to April has the clearest water and calmest sea. October and early November are inside the season but least predictable, with weather cancellations from the tail of the rains. May closes the window on the 15th.
Can you visit the Similans outside the season?
No. From 16 May to 14 October the national park is closed to all visitors, and no operator can legally take you. Phi Phi, Phang Nga Bay and Coral Island run year-round instead.
Updated: {дата публикации}. Prices are operator prices as of August 2026; check the tour card for current rates.
