The Similan Islands are a national park far out in the Andaman Sea, open to visitors only from 15 October to 15 May each year. Most people go on a speedboat day trip from Thap Lamu pier near Khao Lak; divers often choose a liveaboard. Foreign adults pay 500 baht (October 2026), every visitor needs an e-ticket, and numbers are capped.
Mu Ko Similan National Park lies about 70 km off the coast of Phang Nga province. The name comes from a Yawi (Malay) word for "nine", after the nine granite islands that run from north to south. The park was declared in 1982, and Koh Tachai to the north was added in 1988. The Department of National Parks (DNP) closes the whole park every year in the southwest monsoon, when heavy rain and strong waves make the crossing unsafe and the reefs get a rest.
The 2026–27 season starts on Thursday 15 October 2026. The DNP's closing date is 15 May, which falls on Saturday 15 May 2027.
Similan Islands National Park at a glance
- Open season
- 15 October to 15 May every year; closed 16 May to 14 October (DNP)
- Fee
- Foreign adult 500 baht, child (3–14) 250 baht; Thai adult 100 baht (October 2026)
- Tickets
- Compulsory DNP e-ticket for all visitors; foreigners register with a passport number
- Main pier
- Thap Lamu, Thai Mueang district, Phang Nga, about 70 km from the islands
- Crossing
- About 1 hour 30 minutes by speedboat (DNP)
- Park office
- +66 76 453 272
- Closed island
- Koh Tachai has been closed since May 2016; no reopening date announced
The season: exactly when the park is open
The DNP's park page states the schedule plainly: closed for tourism from 16 May to 14 October, open from 15 October to 15 May, every year. The park's own news service repeated those dates in August 2026. Many websites and some tour sellers still say the park opens on 1 October or 1 November. Neither is correct.
Within the season, the most settled weather is usually from December to April. Early in the season, at the end of October, and in the first half of May, conditions can be mixed, and boats can be cancelled on rough days. If the Similans are the main reason for your trip, build a spare day into your plans. The Andaman monsoon pattern is explained in our guide to the best time for the Thai islands.
The park shuts on 16 May and stays shut until 15 October. No day trips, dives or overnight stays are allowed in the closed season. Anyone offering a Similan trip in the monsoon is selling something else, or something illegal.
E-tickets and the daily visitor cap
Since 15 October 2025, every visitor to the Similans, Thai or foreign, must have a ticket from the DNP's e-ticket system. Foreigners register with their passport number. According to the DNP, tickets can be bought in advance or on the day of the trip up to 08:00, when the park makes its final count of visitors. Tour companies normally buy the tickets for their passengers, so you will be asked for your passport details when you book.
The DNP takes this seriously. Operators that declare fewer passengers than they carry, or give the wrong nationality to pay the lower Thai fee, are fined 5,000 baht for a first offence, 20,000 baht for a second and 100,000 baht for a third, and risk losing their permit for the next season. Make sure the name on the ticket is yours.
The park also limits how many people may visit per day. In 2019 the DNP set a ceiling of 3,850 visitors a day, and in March that year Thailand's Supreme Administrative Court confirmed that the department had the power to impose it. We could not confirm on a DNP page whether the same figure applies in the 2026–27 season. In practice, the cap is the reason to book a few days ahead between December and April, especially around Christmas, New Year and Chinese New Year.
Day trips from Khao Lak and Phuket
The standard visit is a speedboat day trip. The DNP names Thap Lamu pier, about 70 km from the islands, as the main departure point, with Patong in Phuket about 90 km away. Boats from Thap Lamu take about an hour and a half to reach Koh Miang (Island 4), where the park headquarters are. The park does not run its own boats; private operators do, and most include hotel pickup in the Khao Lak area. From Phuket, add a road transfer north or a longer boat ride.
A typical day combines two or three snorkeling stops with time on land, usually at Koh Miang and at Koh Similan (Island 8). Koh Similan has the park's best-known view: Sail Rock (Hin Ruea Bai), a granite boulder above a curved white bay, which the DNP calls the highlight viewpoint. Expect a steep scramble over rocks to reach it.
Day trips are long and the open-sea crossing can be rough. Take seasickness tablets before you board, bring a hat and reef-safe sunscreen, and keep valuables in a dry bag. The fee is usually included in the tour price; ask, and check that your operator has your passport details for the e-ticket. Our guide to Khao Lak covers the beaches where most Similan visitors stay.
Liveaboards: diving the Similans properly
Divers often prefer a liveaboard: a boat on which you sleep for two to five nights, diving several times a day at sites a day boat cannot reach comfortably. Trips leave from the Khao Lak area and Phuket. Many itineraries also include sites in the neighboring Mu Ko Surin National Park, such as Richelieu Rock, which DNP divers surveyed in April 2025.
A liveaboard costs much more than a day trip, but you get early-morning and late dives without the long commute, and the crowds of day boats are gone by mid-afternoon. When you compare operators, ask:
- whether national park fees (and how many days of them) are included in the price;
- how many divers share each guide, and what certification level each site needs;
- what safety equipment is on board: oxygen, a first-aid kit, radio and a plan for reaching a hyperbaric chamber. The UK Foreign Office warns that dive operators in Thailand do not always meet safety standards and advises checking exactly these points;
- whether your travel insurance covers diving to the depths you plan.
New divers can learn on the coast first; our guide to learning to dive on Koh Tao explains course levels, and the Gulf island is a common place to qualify before an Andaman trip.
Koh Tachai: still closed
Koh Tachai, the island north of the main group, was annexed to the park in 1988 and has been closed since 15 May 2016 because of damage from heavy tourism. In April 2025, the DNP director-general inspected preparations to reopen it, but no opening date has been announced. In 2026 the park reported green turtles nesting and hatching on Koh Tachai, a sign of recovery. Tours that list it as a stop are out of date.
Rules on the islands
The Similans are a strictly protected marine park. Do not stand on or touch coral, do not feed fish or turtles, and take all your rubbish back to the mainland. The DNP has pursued visitors who harm wildlife: in November 2025, it ordered a search for a tourist filmed offering a wristband to a sea turtle, so the person could be prosecuted. Fishing is banned, and you should keep your distance from nesting turtles on the beaches.
Plastic is a real problem here, too. Park staff regularly remove abandoned fishing nets from the reefs, more than a ton at a time according to DNP reports from early 2026. Bring a refillable bottle, and use the bins on the boat.
Getting to Thap Lamu
The nearest airport is Phuket. The DNP describes the route north by bus or minivan to Thap Lamu, about 100 km from the airport; most tour operators include pickup in Khao Lak, and some in Phuket. By bus from Bangkok, the park's page suggests the Southern Bus Terminal service to Ranong or Phang Nga, getting off at the Thap Lamu junction. Our Phuket guide and the page on transport from Phuket airport cover the first leg.
If you are combining the Similans with other islands, our overview of the lesser-known Andaman islands shows how they connect, and the guide to Khao Sok National Park is the usual inland add-on from Khao Lak. For sea safety in general, see our page on rip currents and beach flags.
Frequently asked questions
When are the Similan Islands open in 2026 and 2027?
The park reopens on Thursday 15 October 2026 and is open until 15 May 2027. Under the DNP's schedule, it is closed every year from 16 May to 14 October. Check with your operator in case bad weather delays the first trips.
How much is the Similan Islands entrance fee?
Foreign adults pay 500 baht and children aged 3 to 14 pay 250 baht (October 2026). Thai adults pay 100 baht. All visitors need a DNP e-ticket, and most tour operators include it in the price and buy it with your passport details.
Is a day trip to the Similans worth it?
Yes, if you like snorkeling and clear water and do not mind a long day with two open-sea crossings. Go between December and April for the best chance of calm seas. If you get seasick easily or have little time, a closer trip from Khao Lak may suit you better.
Can you stay overnight on the Similan Islands?
Divers stay overnight on liveaboard boats. The DNP refers to its season as open for both tourism and overnight stays, but whether land accommodation is offered to the public in a given season changes, so check with the park office before you plan a night on the islands.
Is there a daily limit on Similan visitors?
Yes. The DNP set a cap of 3,850 visitors a day in 2019, upheld by the Supreme Administrative Court. We could not confirm the current figure on a DNP page, but the cap still makes booking ahead sensible in the peak months.
Sources
- Department of National Parks – Mu Ko Similan National Park (checked October 2026)
- Department of National Parks – Similan closes for recovery, e-ticket from 15 October, 16 May 2025 (Thai) (checked October 2026)
- Department of National Parks – Why visit the Similans, open 15 October to 15 May, 7 August 2026 (Thai) (checked October 2026)
- Department of National Parks – Richelieu Rock survey and Koh Tachai reopening preparations, 7 April 2025 (Thai) (checked October 2026)
- Department of National Parks – Green turtle hatchlings on Koh Tachai, 9 March 2026 (Thai) (checked October 2026)
- Department of National Parks – Search for tourist who fed a wristband to a sea turtle, 23 November 2025 (Thai) (checked October 2026)
- Thai PBS – Similan closes for five months, 18 May 2026 (Thai) (checked October 2026)
- Thai PBS – Administrative Court confirms DNP power to limit Similan visitors, 29 March 2019 (Thai) (checked October 2026)
- The Nation – National park fees by category, 7 June 2022 (checked October 2026)
- UK Foreign, Commonwealth & Development Office – Thailand: safety and security (checked October 2026)