Surin or Similan Islands? Which to Visit (and When to Do Both)

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

Surin or Similan Islands: Quick Verdict

Most first-time visitors should start with Similan. It has the widest range of day trips and liveaboards, plus beach stops at Koh Miang. Surin rewards travelers who want shallow-reef snorkeling and fewer crowds. Both parks close in the monsoon, roughly May to October, so check dates before you book anything. Our guide to the park opening dates covers the season window.

• Want beaches and boulder scenery? Choose Similan.
• Want quiet shallows and culture? Choose Surin.
• Want Richelieu Rock or Koh Bon? Book a liveaboard.

Surin vs Similan at a Glance

Similan lies about 70 km off the west coast of southern Thailand. It is part of Mu Koh Similan National Park, which was added to the marine park system in 1983. The park covers nine named islands, extended to 11 with Koh Bon and Koh Tachai. Surin sits north of Similan and has five islands. It has been a national park since 1981. About 150 Moken live there in two small communities. Verify park rules on the national parks authority site.

Snorkeling: Which Park Is Better?

Surin is the stronger pick for shallow coral snorkeling. One Khao Lak operator itinerary stops at Mae Yai Bay, then Chong Kad Bay or Suthep Bay for a long second session. It also includes a Moken village visit. Treat that as an example schedule, not a standard. Similan suits swimmers who want scenery as well. The same operator's route starts at Sailing Rock on Island 8, then moves to Honeymoon Bay and Princess Bay on Koh Miang. Our Similan snorkeling guide covers sites in more detail. Operators quote visibility of up to 30 m at Similan. Read that as a best-case figure.

Diving: Richelieu Rock vs Similan Sites

Divers get a clearer split. Richelieu Rock is the headline Surin site and is a fixture on liveaboard itineraries. Guest reviews rate Elephant Head Rock, Koh Bon and Koh Tachai as top Similan sites. A Phuket-based instructor notes that some day-trip speedboats include Richelieu, but liveaboards are the usual route. Whale sharks and manta rays appear on liveaboard pages, but sightings are never guaranteed. Our Similan diving guide lists the main sites. See the whale shark page for realistic expectations.

Day Trip, Liveaboard or Both? Cost, Time and Access

Day trips leave from Khao Lak. One operator picks guests up between 04:00 and 06:00 and returns the boat to Makham Pier around 16:00. Surin means a longer boat ride and fewer hours in the water. In our editorial assessment, budget roughly ฿2,500–฿5,000 for a day trip. Liveaboards cost more, often ฿18,000–฿40,000 for three to four nights. Quotes vary by boat and season, so ask whether the National Park fee is included. Phuket adds a longer transfer chain, so read our guide to reaching Similan from Phuket. For one-day plans, start with the Similan day trip guide. Day trips usually target one park. A combined trip is a liveaboard, and doing both typically takes about four days and nights. A few operators manage three.

Season, Closures and Conditions

Both parks close in the monsoon, roughly May to October by one operator's account. Some islands also rotate through closures inside the open season. One resort announced a May 15, 2025 closing date, so expect similar timing but check the current year. Water conditions matter for snorkelers. See Similan water temperature for seasonal ranges. Ignore old forum claims about tsunami or typhoon damage. Conditions change, so read recent trip reports instead.

Who Should Pick Which

Match the park to your trip, not to a social media caption.

• First-time snorkeler: Similan day trip.
• Family or non-swimmer: Similan, where beach time on Koh Miang fills the day.
• Photographer: liveaboard covering both parks.
• Certified diver with 3+ days: liveaboard to Richelieu Rock and Koh Bon.
• Tight itinerary: one-day Similan trip.
• Quiet-seeker: Surin day trip or liveaboard.
• Mistake to avoid: booking before checking the season window.
• Mistake to avoid: treating the two parks as one trip.
• Mistake to avoid: ignoring the separate National Park fee.