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 (≈ $136) 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 are the Similan Islands 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 do you get to the Similan Islands?
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 on the Similans — what is the difference?
This is the question that decides which boat you book, and it is not about preference: the diving trip requires a certification. The Similan Islands diving day trip is two certified dives at ฿4,900 (≈ $136) 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.
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 run by Khao Lak Explorer (4.9 from 1,099 reviews) starts at ฿3,490 (≈ $97) per person with the marine park fee already included, and the shared market runs up to about ฿4,100 (≈ $114). That boat is a ten-hour day rather than the dive boat's twelve and a half, and mask, snorkel and fins, a light breakfast and a Thai lunch on the beach come with it.
Snorkelling here counts as a boat tour rather than diving. 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 (≈ $11) 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 (≈ $108–125) for snorkelling against ฿6,000–฿7,000 (≈ $166–194) for two dives. Above about ฿4,300 (≈ $119) the shared-boat market ends: there is no premium snorkelling tier here, only private charters quoted on request.
What you actually see
Where the boat dives depends on the day of the week:
- 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.
- 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.
How much does a day on the Similans cost?
| Item | Cost | USD | Notes |
|---|---|---|---|
| Two-dive day trip | ฿4,900/person | ≈ $136 | includes transfers, breakfast, lunch, soft drinks |
| National park fee | ฿700 | ≈ $19 | cash, collected on the day — not in the price |
| Equipment rental | ฿150–฿500 per item | ≈ $4.2–14 | only if you do not bring your own |
| Private guide (operator option) | ฿2,000/day | ≈ $55 | optional, on request |
So a realistic all-in budget for a certified diver with rental gear is roughly ฿6,000–฿7,000 (≈ $166–194) 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 (≈ $108) or the premium sunrise trip from ฿5,310 (≈ $147).
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.
Two dive boats out of Phuket also run in every month of the year, and neither needs the park to be open: two dives at Racha Yai with Sharkey Scuba, ฿3,690 (≈ $102) per certified diver with transfers, breakfast, lunch and guide included, back at Chalong pier at 15:15.
The other is three dives at the Phi Phi Islands and Shark Point with All4Diving, ฿3,900 (≈ $108) per person plus a ฿600 (≈ $17) marine park fee paid in cash on board. And if the certificate is exactly what you lack, a try dive with Sea Bees is two dives in the sea with an instructor beside you, from ฿5,900 (≈ $163) per person, minimum age ten.
Practical notes
Important
bring ฿700 (≈ $19) 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.
Two dates and one certificate decide this trip. The park runs 15 October to 15 May, and the boat you may board depends on whether you hold a diving certificate: the dive day needs one, the snorkelling day does not. Book inside the first or last week of the window only if you can move the date — the park authority fixes the exact days each season.
Two dates and one certificate decide this trip. The park runs 15 October to 15 May, and the boat you may board depends on whether you hold a diving certificate: the dive day needs one, the snorkelling day does not. Book inside the first or last week of the window only if you can move the date — the park authority fixes the exact days each season.
What 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 of the island is in the what-to-see-in-Phuket guide.
How do you book a tour to the Similans?
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.
