7 Similan Islands Dive Sites: Where to Dive and How to Choose

Featured image: josh.ev9, CC BY-SA 2.0, via Flickr.

Best Similan Islands dive sites at a glance

Seven sites cover most decisions. Koh Bon is for advanced divers, with average depths of 5-40 m (16-131 ft) and stronger currents. Christmas Point has a best area near 24 m (79 ft) and current that trip reports call challenging. Donald Duck Bay is the gentler place to start. Match the site to your certification first, then to the boat's route. Cells marked "ask operator" have no published figure we can attribute.

7 Similan Islands dive sites, site by site

Prices and hours checked November 2026. Entries run from the offshore stops that feed combined itineraries to the island-side dives. Each one links to a dedicated guide.

1. Koh Bon

Koh Bon is the advanced choice and a regular stop on combined Similan and Surin itineraries. Operators describe average depths of 5-40 m (16-131 ft) and visibility of 15-40 m (49-131 ft). Currents run stronger here than at other islands, and mantas are the main draw.

Sightings are a possibility, never a promise, so keep movements slow if a manta appears. Read the Koh Bon dive guide for what to expect underwater. Skip it if you hold a basic Open Water card with few logged dives.

2. Koh Tachai

Koh Tachai is easy to reach from Khao Lak and appears on many liveaboard routes. Its Koh Tachai Plateau dive is the site operators name most often. Koh Bon lies around one hour by boat from here, so the two pair naturally on one itinerary.

Richelieu Rock sits close by but belongs to Mu Ko Surin National Park, not the Similans. Open the Koh Tachai dive guide for site notes and depth planning. Newer divers should ask the boat for the planned profile before choosing it.

3. Elephant Head Rock

Elephant Head Rock is a boulder site named for a rock that resembles an elephant's head. Three rocks break the surface, and the largest gives the site its name. A 2009 forum account places it off the south-west point of Similan 8 and lists it among boulder sites often exposed to current.

Expect jumbled granite rather than a smooth slope, so buoyancy control matters. Use the Elephant Head Rock notes to plan your dive. Divers who dislike current or surge should pick a gentler site.

4. Christmas Point

Christmas Point is a series of underwater pinnacles, with boulders that form tunnels. Operators put the best area at about 24 m (79 ft), where coral gardens sit. Large fish rest in the crevices, but trip reports from a Khao Lak operator call the current here challenging.

A 2009 account places a boulder breaking the surface off the north-west point of Similan 9. See the Christmas Point dive guide before you commit. Skip it if your current experience is limited to drift dives on gentle slopes.

5. Donald Duck Bay

Donald Duck Bay is a starting point on Koh Similan, and a local visitor guide recommends it as a place to begin. Green turtles, crustaceans, gastropods and shrimps are the usual sightings, with moray eels at night. Views above the surface are part of its reputation, and snorkelers can use the shallows.

Read the Donald Duck Bay dive guide for the bay in detail. Skip it if big pelagics are your priority, and look to Koh Bon instead.

6. Similan Island 4

Similan Island 4 is one of the numbered islands in Mu Ko Similan National Park. No depth, current or visibility figure for it comes from a source we can attribute. A 2009 account places Morning Glory, a gently sloping drift reef, off Similan 5, next in the numbering.

Treat Island 4 as an ask-the-boat stop and request the day's dive plan. Browse the Similan Island 4 guide for area notes. Skip pinning a whole trip to it unless the operator names the exact site.

7. Similan Island 8

Similan Island 8 is the area where several 2009-era site leads cluster. Elephant Head Rock lies off its south-west point in that account. Fantasea Reef, on the west side of Similan 8, was reported closed to divers in 2009.

Park closures change, so ask which Island 8 sites a boat may dive this season. Read the Similan Island 8 dive guide for the island overview. Skip it if you need a fixed, guaranteed site list before booking.

Which Similan Islands dive sites suit which diver

Group sites by current, not by fame. A 2009 forum account describes East of Eden (off Similan 7) and Morning Glory (off Similan 5) as gently sloping reefs suited to drift diving. That account lists Christmas Point, Elephant Head Rock, Sharkfin Reef and Boulder City as boulder sites often exposed to current. Because it is old, ask a current guide whether it still holds.

• Gentler and drift-style: Donald Duck Bay, plus East of Eden and Morning Glory from the 2009 account.
• Boulder and current-prone: Elephant Head Rock and Christmas Point.
• Advanced and deep: Koh Bon, with depths to 40 m, and Beacon Point on Koh Similan, which drops to 40 m.

Day boat or liveaboard?

Day trips from Khao Lak run two dives, with journeys of 50-80 minutes depending on the site. One operator schedules Richelieu Rock three days a week and other sites, such as Koh Bon, on other days. Its 4-night liveaboard to the Similans, Koh Bon, Koh Tachai and Richelieu lists 14 dives from ฿29,190. A 5-night version lists 18 dives from ฿36,487. These are one operator's examples, not market rates, and prices vary by operator, cabin and season. Count nights and dives, not the trip label, because the same trip appears as both "4 day" and "5 days, 4 nights".

Season, conditions and park rules

Operator schedules run from October to May, with liveaboard departures listed from October 2026 through May 2027. Exact opening dates, fees and permitted sites come from the Department of National Parks. Reports from 2009 say Similan 1, 2 and 3 and Fantasea Reef were closed to divers. Ask your operator which sites are open today. Water averages about 77°F (25°C) according to one local guide. Agree suit hire in advance rather than assuming warm water means no exposure protection.

Certification, depth and current: what you need

One Khao Lak liveaboard requires certification to 30 m (98 ft), or an onboard upgrade, for Open Water divers. That is a rule of that program, not of the park. Koh Bon reaches 40 m (131 ft), and Beacon Point on Koh Similan drops to 40 m too. Tell the dive center when you last dived and how many dives you have logged. Book a refresher before the trip if you need one.

Getting there and where to base yourself

Khao Lak is the departure point for the Similan and Surin trips described here, with day journeys of 50-80 minutes. Transfer times from Phuket vary by operator, so ask your dive agency for the pickup plan. Ask the same agency for your no-fly interval, because returning to the pier does not reset the clock.

Snorkelers and non-divers

A companion may join if the product accepts non-divers. Ask whether it includes snorkeling stops with supervision, not only a place aboard. A snorkeling ticket does not include diving. Donald Duck Bay has shallows that snorkelers can use.

Mistakes to avoid

Most booking errors come from reading the package title instead of the route.

• Booking by package title without asking which sites the boat will visit.
• Overestimating your certification: depth rules are boat-specific, such as the 30 m (98 ft) requirement on one liveaboard.
• Assuming a snorkeling ticket includes diving.
• Trusting the trip label instead of the nights and dives listed.
• Overlooking that Richelieu Rock sits in Mu Ko Surin National Park, so park charges differ from Similan sites.
• Booking a flight home for the last dive day without asking about the no-fly interval.