The Similan Islands Explained: A Guide to Islands 1-9, Koh Bon and Koh Tachai

Quick answer

The Similans began as nine numbered islands, but Mu Ko Similan National Park now contains eleven because Koh Bon and Koh Tachai were added to the protected area. The Classic Similan Islands snorkelling trip sold on this website does not visit all nine original islands or all eleven park islands. It normally combines selected snorkelling areas with permitted beach stops on Islands 4 and 8, while the exact route can change for park instructions, weather, sea conditions, tides and safety.

Last reviewed: 25 August 2026 by Visit Similan Islands, a specialist North Andaman planning and booking service. We compare current official visitor guidance with the trips we actually offer, and we check the exact route and availability before booking.

The Similan Islands at a glance

• Nine original islands: numbered from Island 1 in the south to Island 9 in the north.
• Eleven park islands: Koh Bon and Koh Tachai are also part of Mu Ko Similan National Park.
• Main visitor islands: Island 4 is commonly used for beach, lunch and rest time; Island 8 is associated with Sailing Rock, the viewpoint and the classic granite-boulder scenery.
• Protected southern islands: Islands 1–3 are conservation-first areas rather than normal visitor-landing stops.
• Koh Tachai: the island remains closed to tourist landings for natural recovery, although some of the scuba and liveaboard routes sold on this website may use surrounding waters.
• No island accommodation: current official visitor guidance permits day visits only; overnight stays on the Similan Islands themselves are not available.

The name “Similan” comes from a Malay word for nine. The original chain was numbered from Island 1 in the south to Island 9 in the north. Koh Bon and Koh Tachai were later added to the national park, creating the eleven-island protected area described today.

The ASEAN Centre for Biodiversity records Mu Ko Similan National Park as covering about 140 square kilometres. Only a relatively small part is island land; the marine environment is the main reason the park exists.

Why island names can be confusing

English spellings vary. Miang may appear as Meang, Bangu as Ba Ngu, and Thap Lamu as Tap Lamu or Tub Lamu. Older English-language guides and dive maps also number or name some of the small central islands differently.

For this visitor guide, we follow the Tourism Authority of Thailand’s April 2026 national-park overview: Islands 5 and 6 are left as numbered central islands, and Island 7 is identified as Koh Payu. When choosing one of the snorkelling, scuba or liveaboard trips sold on this website, its confirmed programme and dive-site briefing matter more than relying on an old island-number graphic.

Island 1: Koh Hu Yong

Island 1 is the southern end of the original chain. It is closely associated with sea-turtle conservation and is not a normal tourist beach stop.

What travellers need to know:

• Do not expect a landing.
• Protection matters more than ticking it off a sightseeing list.
• A boat passing nearby does not mean visitors can enter a protected beach.

Island 2: Koh Pa Yang

Island 2 is another small southern island. It is not one of the standard lunch or viewpoint stops on the main snorkelling day trip. Its value is part of the wider protected chain: reefs, coastal habitat and space where wildlife is disturbed less often than on the visitor islands.

Island 3: Koh Pa Yan

Island 3 is also outside the normal visitor-landing programme. The three southern islands are best understood as conservation-first areas rather than missed attractions.

Island 4: Koh Miang

Koh Miang is one of the principal visitor islands. The Classic Similan Islands snorkelling trip sold on this website normally uses it for beach time, lunch, rest and access to national-park visitor facilities.

• Permitted beach areas
• Lunch and rest time
• Forest habitat and birdlife
• National-park facilities

It is the island most likely to answer the question, “Where do we have lunch and beach time?” The exact permitted beach and timing still depend on the operating plan and park instructions.

Islands 5 and 6

The Classic Similan Islands snorkelling trip sold on this website normally plans its first snorkelling session around Islands 5 and 6. These are better presented as marine and snorkelling areas than as places where guests should expect a long beach visit. The actual entry point depends on conditions and the guide’s plan.

Island 7: Koh Payu area

The Tourism Authority of Thailand’s current 2026 visitor guide identifies Island 7 as Koh Payu. Some older English pages and dive maps use different numbering around the central rocks and islands, which is why this part of the chain can look inconsistent online.

For travellers, the useful point is simple: use island numbers to understand the broad park layout, but rely on the confirmed programme for the exact Classic, Early Bird, scuba or liveaboard trip selected on this website.

Island 8: Koh Similan

Island 8 is the largest of the original nine and the best-known visitor island. It provides much of the scenery people picture when they think of the Similans.

• Sailing Rock
• The viewpoint route when open
• White sand and enormous granite boulders
• Donald Duck Bay and the surrounding seascape

The viewpoint may be restricted because of weather, crowding or safety, so it should be treated as a possible part of the visit rather than an unconditional promise.

Island 9: Koh Bangu

Koh Bangu is the northernmost of the original nine. The waters around it are used for snorkelling and diving, with the exact location chosen according to conditions.

Christmas Point is a recognised dive site around the north-west of Island 9. A snorkelling day trip may use a suitable area around the island, but snorkellers should not assume they visit the same depths or formations as scuba divers.

Koh Bon

Koh Bon lies north of the original nine and forms part of the national park. It is primarily known as a scuba-diving destination with wall, reef and ridge terrain.

Manta rays are possible, but wildlife sightings are never guaranteed. Koh Bon is not a routine beach stop on the standard Similan snorkelling itinerary.

Koh Tachai

Koh Tachai is farther north and is also part of the national park. The Tourism Authority of Thailand’s 2026 guidance says the island remains closed to tourist landings for natural recovery. If a scuba or liveaboard trip sold on this website uses surrounding waters, that does not mean guests can go ashore.

Which islands will my trip actually visit?

The current Classic Similan Islands snorkelling trip sold on this website normally plans:

• Snorkelling around Islands 5 and 6
• Beach and lunch time on Island 4
• Snorkelling in a suitable area around Island 9
• Beach and possible viewpoint time on Island 8

This is a typical programme, not a guarantee. Weather, sea conditions, tides, safety, crowd management and national-park instructions can change the sequence or stops. Visit Similan Islands checks the current programme and availability before taking a booking.

Frequently asked questions

How many Similan Islands are there: nine or eleven?

Both numbers appear for a reason. “Similan” refers to the original nine-island chain. Mu Ko Similan National Park now contains eleven islands because Koh Bon and Koh Tachai were added to the protected area.

Does a day trip visit all nine original islands?

No. The Similan snorkelling day trips sold on this website use selected snorkelling areas and permitted visitor islands. Trying to “tick off” every island is neither part of those programmes nor the purpose of visiting a protected marine park.

Which Similan islands can tourists visit?

Islands 4 and 8 are the main visitor islands in current official guidance. Other islands may be seen from the boat or used for suitable snorkelling or diving areas, but landing and activity rules depend on park instructions. Koh Tachai remains closed to tourist landings.

Can I stay overnight on the Similan Islands?

No. Current official guidance allows day visits only, and overnight accommodation on the islands is not available. Certified divers who want a multi-day North Andaman experience can consider a scuba liveaboard, subject to suitability and availability.

When is the Similan Islands visitor season?

The established annual national-park visitor season is 15 October to 15 May. Individual departures, routes and temporary access can still change because of weather, safety or a specific park notice, so check the actual date before booking.

Choose the Similan trip that fits you

If reaching the islands earlier and aiming for quieter beach time matters most, compare the Early Bird Similan Islands trip. If you prefer the straightforward standard day, see the Classic Similan Islands snorkelling trip. You can also read our guide to Similan snorkelling areas before deciding.

How this guide was checked

This article was reviewed against the Tourism Authority of Thailand’s April 2026 national-park overview, the ASEAN Centre for Biodiversity’s Mu Ko Similan park profile and the current visitor programme offered by Visit Similan Islands. Official park notices override general guidance, and an exact trip route is always checked before booking.

• Tourism Authority of Thailand: Mu Ko Similan National Park, updated April 2026
• ASEAN Centre for Biodiversity: Mu Ko Similan heritage-park profile