Similan Islands Opening Date: When the Park Reopens Each Year

Featured image: KOSIN SUKHUM, CC BY-SA 4.0, via Wikimedia Commons.

When Do the Similan Islands Open? (Short Answer)

Similan Islands National Park in Phang Nga closes every year from 15 May to 15 October. Reopening is therefore in mid-October. For 2026, an operator notice lists 15 October 2026 as the day the park reopens. Some pages count 15 October as the last closed day, which would make 16 October the first open day. Both readings agree on the same week, so plan around mid-October rather than a single hour.

Today is 12 November 2026, so the 2026-27 season is underway. Operators in Phuket were describing Similan and Surin as open in their early-November posts. Last verified 12 November 2026 against those operator notices. Park announcements from the Department of National Parks are the final word on dates.

Keep three dates apart in your planning. The park reopening date is when visitors may enter. The first tour date is when an operator actually sails. A liveaboard start date is when a specific boat departs, and it is often later than both.

Annual Open and Closed Dates

The closure lasts six months and repeats on the same calendar pattern. It protects visitors from rough monsoon seas. It also gives reefs, trails and beaches a rest from foot traffic and boat anchoring. Authorities treat it as both a safety measure and a conservation measure.

Use the table as a pattern, not a promise. Year-specific dates can shift, so only the 15 May and 15 October markers are reported.

How to Confirm Current Status Before You Book

Start with the Department of National Parks site at dnp.go.th and its park announcements. Look for notices about Similan Islands National Park, not general tourism pages. Official notices override any older blog post or social media video.

Then ask your operator direct questions. Ask whether the boat has a confirmed departure for your date. Ask which islands are included on that day. Ask what happens if a weather closure cancels the trip, and whether you get a refund or a rebooking. Operators answer these differently, so get the terms in writing.

Ignore posts dated 2024 or 2025. Pages about earlier seasons keep ranking long after their dates have passed. Always read the date on a notice before you rely on it.

• Check the Department of National Parks for the current park notice.
• Ask the operator for the confirmed first departure date.
• Ask which islands are open on your date.
• Ask about weather cancellation, refund and rebooking terms.
• Note the date on every page you rely on.

Best Time to Visit Within the Open Season

Opening week and mid-season suit different travelers. The case for opening week is reasoning, not data. Reefs have rested for six months and visitor numbers may be lower. The risk is rougher seas and fewer operators running full schedules. Late in the season, boats are more regular, but the 15 May closure sets a hard stop.

For month-by-month sea conditions, see our guide to water temperature by month. No visibility or crowd figures are claimed here.

Getting There After Opening: Phuket, Khao Lak, Ranong

Similan Islands sit about 84 km northwest of Phuket. The archipelago has 11 islands. Boats leave from Phuket (Chalong and Patong), from Thap Lamu near Khao Lak, and from Ranong.

From Phuket, boat travel takes roughly 2 to 4 hours depending on departure point, boat type and island. Koh Similan takes about two to three hours. Koh Tachai takes up to four hours. Khao Lak is closer, at around two hours to the islands.

Phuket has more departures but a longer, earlier day. Some Phuket day tours use a road transfer to the Thap Lamu mainland area before boarding. Khao Lak and Thap Lamu sit nearer the boats but offer fewer flights. Our Phuket departure guide covers the details. Bangkok is about 570 km away, and a night bus to Ranong or Khao Lak takes around 13 hours in total.

Day Trip, Overnight, or Liveaboard?

Your time and budget decide this. Day trips fit one free day and a base in Phuket or Khao Lak. Overnight stays and liveaboards fit divers who want more dive sites and less transit.

Read our day trip planning guide if you have one day. Divers can compare routes in the Similan diving guide. Snorkelers will find reef notes in the snorkeling guide. If you are weighing parks, the Surin comparison follows naturally from the opening dates. Surin and Tarutao were reported to reopen in the same season as Similan in 2024, but check Tarutao's own schedule.

• One day only: book a day trip from your base.
• Two to three days: consider an overnight stay near the departure pier.
• Diving focus: compare liveaboard itineraries and ask about the start date.
• Whale shark hopes: read our whale shark notes and expect no guarantees.

Mistakes to Avoid When Planning Around the Opening

Most errors come from old information or mixed-up dates. Avoid them with a short checklist.

• Booking before the reopening date is confirmed.
• Assuming day trips and liveaboards start on the same day.
• Relying on 2024 or 2025 posts for 2026-27 dates.
• Ignoring the date stamp on a notice.
• Planning a late trip without allowing for the 15 May closure.