Similan Islands

Thailand’s top-rated marine park, closed half the year

The Similan Islands sit about 70 km northwest of Phuket in the Andaman Sea, part of a national park that the Thai government closes every year from around May 15 through October 31. The closure is not a formality — it’s enforced. The park’s dive sites, beaches, and camping areas are genuinely inaccessible during the monsoon months, and the ecosystem has measurably recovered because of it.

The islands are ranked among the top ten dive sites in the world by multiple dive bodies. This isn’t just promotional language: the Similans have exceptional coral coverage, reliably clear water (15–30 meter visibility during the dry season), and a marine life density that includes sea turtles, leopard sharks, manta rays, and whale sharks. The snorkeling is unusually good even by Andaman standards, because the reef begins at shallow depths on several islands.

There are nine islands numbered rather than named (though they’ve acquired informal names over time). Island 4 is where day-trip boats stop for snorkeling. Island 8 has the most famous boulder formations — Hat Fan Lae Bay and “Donald Duck Bay,” a bay named for a distinctive rock formation. The dive sites for advanced divers concentrate around Islands 7, 8, and 9.

Where	~70 km northwest of Phuket, Andaman Sea
Cost	National park fee 500 THB; day trips 2,500–5,000 THB
Time needed	1 day from Khao Lak, or 3–7 days liveaboard
Getting there	Speedboat from Tab Lamu Pier, Khao Lak, 45–60 min
Best time	Mid-November to mid-May only (park closed otherwise)

Getting there: Khao Lak vs. Phuket departure

The most practical base for visiting the Similans is Khao Lak, a beach town about 90 km north of Phuket. Tab Lamu Pier in Khao Lak is 45–60 minutes by speedboat from the islands, making day trips genuinely manageable. Most organized tours depart around 08:00 and return by 17:00.

From Phuket, day trips to the Similans are possible but long. Departures typically leave Phuket around 06:00 and the total travel time is 2.5–3 hours each way, leaving perhaps 5–6 hours at the islands. This is workable but tiring; overnight stays in Khao Lak before or after are worth considering.

Similan Islands snorkeling and diving day trip from Khao Lak

The national park fee (500 THB per person) is charged separately from tour costs at the pier, though many organized tours include it.

Diving at the Similans

The Similan Islands are a genuine destination for serious divers, not just a backdrop for snorkel tourism. The dive sites range from easy, shallow reef dives accessible to newly certified divers to technically demanding walls and seamounts.

Key sites include:

• Elephant Head Rock (Island 8): A labyrinth of granite boulders at 5–30 meters with strong currents and dense soft coral. Leopard sharks, large grouper, and schools of batfish. Intermediate to advanced.
• Beacon Reef (Island 9): Wide sandy slopes at 6–25 meters, excellent for beginners. Sea turtles and reef sharks sighted regularly.
• East of Eden (Island 7): Soft coral wall starting at 8 meters. Strong current site; best for advanced divers. Giant gorgonians visible from 20 meters down.
• Fantasea Reef (Island 5): Boulder formations, moray eels, and lionfish. Mixed-level site suitable for most certified divers.

Scuba diving at King Cruiser Wreck and Shark Point

Dive operators in Khao Lak typically offer 2-dive day trips for 3,500–5,000 THB (€93–132) including gear, or PADI Open Water certification courses over 3–4 days for 15,000–18,000 THB (€398–477). Several operators also run multi-day liveaboards at 12,000–25,000 THB (~€318–663) depending on boat quality and number of dives included.

For a comparison of Similan diving vs. other Andaman sites, see Similan Islands diving guide and scuba diving in Phuket overview.

Snorkeling for non-divers

Non-divers are well-served at the Similans, particularly around Islands 4 and 8, where the coral begins at 1–2 meters depth. Operators provide basic snorkeling equipment (mask, fins, snorkel) on all day trips. The water is genuinely clear by Andaman standards — even at the surface, you can see coral formations at 5–8 meters.

The main constraint is weather: swells in November and early December can reduce visibility and make surface conditions uncomfortable. January through March is optimal for snorkeling conditions.

A day trip from Khao Lak costs 2,500–4,500 THB (~€66–119) per person including snorkeling gear, lunch, and the national park fee when the fee is bundled. Budget separately for food and drinks unless the tour specifies full board.

Similan Islands snorkeling day trip with meals from Khao Lak

Month-by-month conditions during the open season

Months	Conditions	Notes
Mid-Nov–Dec	Improving visibility, some swell early	Fewer crowds than peak
Jan–Mar	Best visibility (15–30 m), calmest seas	Peak season, busiest boats
Apr–mid-May	Warming water, occasional early swell	Good value, park closing soon
Mid-May–Oct	Park closed	No access; plan elsewhere

The park’s exact opening and closing dates shift by a week or two each year depending on sea conditions, so travellers visiting right at the edges of the season (early November or late April) should confirm current status with a Khao Lak operator before booking transport.

The camping option

The national park operates a limited number of camping spaces on Island 4. This is a legitimate way to experience the islands at dawn and dusk, when day-tripper boats have left. Tents are available for hire (about 450 THB per night per person), and the park operates a basic canteen. Campers must arrive and depart on the park’s own supply boats, which run on a fixed schedule. Availability is limited — book directly through the national park (Mu Ko Similan National Park) several weeks in advance during peak season.

Overnight stays are not glamping. The facilities are simple, insects are abundant, and supplies brought from the mainland are limited. The payoff is the islands without day-trip crowds, particularly for photographers.

Whale sharks, manta rays, and what to realistically expect

Whale shark sightings at the Similans are real but not guaranteed. The species is migratory and tends to appear around the northern islands (8 and 9) from January through April. A sighting on any given dive trip is not certain — in a typical dry season, experienced local divers might see whale sharks on 1 in 6 or 8 trips. Manta rays are sighted less frequently but are confirmed visitors to several sites.

The Surin Islands at Richelieu Rock (accessible from Khao Lak) have a higher documented whale shark encounter rate than the Similans. If whale shark sightings are your primary goal, Richelieu Rock is the better bet.

What the park closure means for travel planning

The closure dates shift slightly each year but consistently run from approximately May 15 to October 31. Checking current dates with the national park or your Khao Lak dive operator before finalizing travel dates is important. Travelers arriving in May or November on the cusp of the closure/opening sometimes find the park not yet accessible even if official dates suggest otherwise — conditions determine the actual opening.

For rainy season alternatives, Koh Lanta stays open year-round and is popular among divers during the low season. Khao Sok national park is a completely different environment but offers year-round access and excellent wildlife.

See also best time to visit Phuket and Phuket in monsoon season for seasonal planning.

What to pack for a Similan Islands day trip

A rash guard or wetsuit top helps against both sun and jellyfish (occasional, not common) during long snorkeling sessions. Reef-safe sunscreen is worth prioritising here specifically — the coral coverage is exceptional and part of why the islands are protected. Motion sickness tablets are sensible for the speedboat crossing, particularly from Phuket where the journey is longer. Bring cash for the national park fee if it isn’t bundled into your tour, plus a dry bag for phones and cameras on the boat. Divers should bring certification cards and log books if pursuing an Advanced course or planning to dive with a new operator.

Comparing the Similans to other Phuket dive and snorkel trips

	Similan Islands	Racha Island	Coral Island
Travel time from Phuket	2.5–3 hrs (or 45–60 min from Khao Lak)	20–30 min	15 min
Season	Nov–May only	Year-round (weather-dependent)	Year-round
Visibility	Excellent (15–30 m)	Good (10–20 m)	Fair–good
Best for	Serious diving, top-tier snorkeling	Easy diving, quieter island day	Quick family beach day

For the closer, shorter options, see Racha Island and Coral Island; for the Similans’ closest rival for whale sharks, see Surin Islands.

Frequently asked questions about Similan Islands

Can you visit the Similan Islands from Phuket?

Yes, but it’s a long day. The journey from Phuket is approximately 2.5–3 hours by speedboat, compared to 45–60 minutes from Khao Lak. Most tour operators depart Phuket around 06:00. If you have one full day for the Similans, Khao Lak is a much more practical base — consider an overnight stay there before or after.

When are the Similan Islands open?

The national park opens approximately mid-November and closes mid-May every year. The exact dates shift slightly each season. No commercial tours or dive boats are permitted during the closure. Check current dates with dive operators or the national park authority before booking.

Is diving at the Similans suitable for beginners?

Yes, several sites are appropriate for newly certified (Open Water) divers. Beacon Reef on Island 9 and sites around Island 4 are shallow and calm. More advanced sites like Elephant Head Rock and East of Eden require at least Advanced Open Water certification and experience with current diving. Reputable operators will match you to appropriate sites for your certification level.

Do I need to book the Similan Islands day trip in advance?

During peak season (December–March), day trip boats from Khao Lak can fill up several days to a week in advance. Liveaboards book out weeks or months in advance. January–February is the busiest period. Off-peak (November, April) you can often book 1–2 days ahead without difficulty.

Can I stay overnight on the Similan Islands?

Yes, through the national park’s camping area on Island 4. Tents are available for hire, and basic meals are served at the park canteen. You must book through the national park (Mu Ko Similan National Park) directly. Capacity is limited and booking ahead during high season is essential. There are no private resorts on the islands.

Are the Similan Islands worth visiting if I don’t dive?

Yes — the snorkeling is among the best in Thailand, and the above-water scenery of Island 4 (Hat Fan Lae Bay) and Island 8 is impressive. The beaches are clean, the boulders are photogenic, and the water is warm year-round. That said, the islands are primarily known as a dive destination. If snorkeling is your only activity, Phi Phi Islands and Surin Islands are more logistically convenient from Phuket.

Is the national park fee included in tour prices?

Not always. Some operators bundle the 500 THB per person national park fee into their advertised price; others add it separately at Tab Lamu Pier. Check when booking. Snorkeling equipment, lunch, and transfers from your hotel are also variably included — read the inclusions carefully.

What’s the difference between the Similan Islands and the Surin Islands?

Both are national park archipelagos in the Andaman Sea, both close June–October, and both are accessed from Khao Lak. The Similans are larger, better known, and have more diverse dive sites. The Surins (including Richelieu Rock) have a higher probability of whale shark encounters and are considered a more specialized dive destination. See Phi Phi vs Similan comparison for details.

Is it better to visit the Similans from Phuket or stay in Khao Lak first?

Staying in Khao Lak the night before is significantly better if your schedule allows it. It cuts the one-way travel time from 2.5–3 hours to 45–60 minutes, means an earlier and less rushed start, and gives you the option of an easier return. If you only have limited time and want to stay based in Phuket, it’s still doable, just a longer day.

Can beginners snorkel at the Similan Islands, or is it diving-only?

Snorkeling is well-suited to complete beginners — the reef at Islands 4 and 8 starts in shallow water, and boats provide basic equipment plus flotation aids. No experience or certification is required. Strong swimming ability isn’t strictly necessary if you use a life jacket, though comfort in open water makes for a better experience.