Diving The Similan Islands 2025: A Quick Guide

Diving the Similan Islands is one of Thailand’s great adventures, especially from a liveaboard boat. Here’s a quick guide about what to expect from Similan liveaboard diving.

Pook and yellow snapper, Richelieu Rock © chris@divehappy.com

What’s Special About The Similan Islands? Why Would You Go There For Diving?

The Similan Islands are the best place to go scuba diving in Thailand. The nine islands of the Similan Islands themselves along with the northern islands of Koh Bon, Koh Tachai and Richelieu Rock, widely considered to be Thailand’s best dive site, provide a tremendous variety of underwater environments during a typical 4 day Similan liveaboard.

I’ve done a total of six liveaboards during the Similan 2023 – 2024 season – you can see my Similan liveaboard trip reports describing what we saw on each trip. I’ve just got back from my first trip of the Similan 2024 – 2025 season – here’s my November 2024 Similan liveaboard trip report.

Huge school of fusiliers © chris@divehappy.com

Huge schools of fusiliers, jacks, barracuda, yellow snapper and batfish are common, alongside stunning soft coral reefs at Richelieu Rock and Three Trees, and magnificent hard coral gardens in the Surin Islands. Turtles are also frequently encountered and often are completely unbothered by divers.

Manta Ray and ramoras, Koh Bon, Thailand © Chris Mitchell

Koh Bon is a renown manta ray hotspot with several sightings each season. Whale sharks are similarly occasionally spotted at Richelieu Rock and other sites too. There is also a smorgasbord of smaller critters – seahorses, harlequin shrimp, ghost pipefish and hundreds more.

Conditions are usually calm seas and great visibility, although there can be squalls of rain passing through.

Turtle, Three Trees © chris@divehappy.com

On the surface, the Similan Islands are famous for their pristine white beaches. You’ll see Donald Duck Bay come up again and again in Thailand promotional literature. You will probably also experience spectacular sunrises and sunsets in the Similans too.

In short, you can see a huge variety of marine life at an affordable price in the Similan Islands. For many people, it’s their first experience of doing a liveaboard and usually not their last.

School of Jacks with James, Richelieu Rock, Thailand © Chris Mitchell

What Can I Expect To See In The Similan Islands?

Big and small, the Similans has got it all. The great thing about being on a liveaboard is that over the course of four days you move through a variety of environments, both underwater and above water, and because of that, you see a huge variety of different marine life too.

Batfish and fusiliers, Koh Tachai © chris@divehappy.com

Great Visibility and Lots of Fish

The Similan Islands often has excellent visibility of 20 metres or more which lets you get the proper panoramic feeling when looking out into the blue. There are moments when it can feel like being in a fishbowl at Koh Tachai, West of Eden or Richelieu Rock because you’re surrounded by fish, to the point of it being hard to see your dive buddy.

However, don’t expect the water to be gin clear all the time – it can get cloudy and green at times, and there can be thermoclines too.

House-sized boulders, West of Eden © chris@divehappy.com

Big Boulders The Size Of A House

The visibility also lets you take in the different underwater environments of the various dive sites. West of Eden and Christmas Point are big boulder sites, rocks the size of a house piled up together that have been shaped by centuries of currents – pass over the top of one of them into the blue and it feels like you’re skydiving in slow motion as you see the sandy bottom several storeys below.

3 fans and soft corals, Christmas Point © chris@divehappy.com

The big rocks provide shelter for fish and coral alike, and there are some spectacular arrays of fan corals in the channels between them. There are similar amazing fan corals at Koh Tachai on the second pinnacle.

Pook and the tsunami memorial © chris@divehappy.com

Super White Sand

Other sites, like Three Trees and Hideaway Bay, have the pristine white sand for which the Similan Islands is famous. This makes for great beaches but underwater it’s just as beautiful especially in the shallows. There is a moving memorial to the victims of the 2004 tsunami at Hideaway Bay, the structures surrounded by the bay’s white sand.

Glassfish and soft coral, Richelieu Rock, Thailand © Chris Mitchell

Spectacular Soft Corals

While a couple of the Similans’ signature dive sites like East of Eden and Anita’s Reef remain closed to protect the corals, there are some amazing soft corals to be seen at Three Trees, Koh Tachai and especially Richelieu Rock. Richelieu in particular is spectacular because virtually all of the rock is covered in red and purple soft corals

Manta ray approaching, Koh Bon, Thailand © Chris Mitchell

Maybe A Manta Ray

Manta rays are among the most amazing marine life you can hope to see anywhere in the world, and they are regular visitors to the Similan Islands. Koh Bon is the hotspot for manta rays and if you’re lucky, you’ll get a close encounter rather than just a glimpse.

Sunburst over hard corals, Ao Suthep © chris@divehappy.com

Hard Coral Cafe

While soft corals have got the bright colours, hard corals have got the remarkable spiky shapes – Three Trees and especially Ao Suthep in the Surin Islands have some jaw dropping examples of hard corals that have been able to grow and thrive for decades.

What are the stand out dive sites at the Similan Islands?

There are 20 to 30 dive sites in the Similan Islands – here are a few of the stand out sites.

Yellow snapper beneath Richelieu Rock © chris@divehappy.com

Richelieu Rock

Deservedly renown as Thailand’s best dive site, Richelieu Rock is a submerged horseshoe-shaped rock in the open ocean which provides shelter for all manner of marine life, big and small. The limestone rock is covered in bright red and purple soft corals, over which thousands of glass fish move in synchronicity. Out in the blue the action kicks off as big schools of jacks and fusiliers race over and past the rock, only to regroup and do it all over again.

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Barracuda and batfish groups like to hang just off the rock, moving at a far more sedate pace. The calmer area inside the horseshoe is home to a big school of yellow snapper, and in the nooks and crannies of the limestone rock harlequin shrimp, seahorses and ghost pipefish can often be found. Most trips do at least two dives on Richelieu, but it’s a site that would repay multiple days of diving without getting board. The sheer dynamism of life around Richelieu Rock over the course of a day means that every visit is different.

Yellow coral and diver, Koh Bon Pinnacle © chris@divehappy.com

Koh Bon Pinnacle

As well as Koh Bon discussed above, the nearby Koh Bon pinnacle is a gorgeous, relatively small site which has its craggy limestone rocks covered in bright yellow soft corals. (So much so it’s known as Hin Luang, Yellow Rock, in Thai). If a manta ray shows up here during your dive you’ve hit the Similans jackpot.

Fusiliers and sunburst, Koh Tachai © chris@divehappy.com

Koh Tachai

Notorious for unpredictable strong currents, Koh Tachai’s turbulence is also what makes it a magnet for big schools of fish to ride the currents and feed. Over on the second pinnacle there are some gorgeous fan corals and soft corals clustered together – if the current will let you get over there to see them.

Big Barrel Sponge, Three Trees © chris@divehappy.com

Three Trees

Down in a sandy channel that has to be judged right to avoid ripping currents, Three Trees has some amazing big bommies suffused in soft corals and glass fish, along with a barrel sponge as big as your dive buddy.

Curved rock, Christmas Point © chris@divehappy.com

Christmas Point

The shaped big boulders of this site give it a character all of its own, especially on the first dive of the day in the early morning light. Peering out into the blue while hovering on top of the rocks often results in spotting black tip reef sharks hunting along the boulder’s edge.

Just hatched – Shark’s Fin Reef © chris@divehappy.com

Shark’s Fin Reef

Named because it supposedly looks like one, Shark’s Fin Reef is a huge lozenged-shaped pile of big granite rocks which create numerous plateaus and hideyholes. To my mind, when you can see the whole site below you thanks to good viz, it looks curiously man-made, like a sunken tomb. Shallowing up there is usually a plethora of fish gathering to ride the currents and hunt for food. This site has a real charisma all of its own.

Manta Ray flyover (nickname Jumbo), Koh Bon, Thailand © Chris Mitchell

Will I Definitely See A Manta Ray or A Whale Shark in the Similan Islands?

The short answer is no. Any dive trip operator that says you’ll definitely see a manta ray or a whale shark in the Similan Islands is not being truthful. They do make appearances throughout the season but there’s no guarantee they will be present on your dive trip. That said, diving at Koh Bon does give you the best chance of being in the right place to see a manta ray, and they’ve been known to show up at Koh Tachai, Three Trees and Richelieu Rock too. Whale sharks seem to favour Richelieu Rock, making an appearance several times each season.

What Does a Similan Liveaboard Itinerary Typically Look Like

A four days / four nights Similan liveaboard itinerary will go something like this:

Day 1: arrive into Phuket Airport, go to boat in the evening. Sail overnight to the Similan Islands
Day 2: Four dives a day, starting at 06.30 in the morning.
Donald Duck Bay / West Of Eden / Three Trees / Turtle Rock (night dive)
Day 3: Christmas Point / Koh Bon / Koh Tachai – 2 dives
Day 4: Ao Suthep (Surin Islands) / Richelieu Rock – 3 dives
Day 5: Koh Bon and / or Koh Bon Pinnacle – 2 dives. Out of the water by 11 am. Back in at Tapla Mu pier 3 to 4pm.
Onward travel to your hotel in Khao Lak or Phuket organised by the boat.

See my Similan liveaboard trip reports from 2022, 2023 and 2024 for a sense of what to expect from each dive site:

Similan Islands Liveaboard Trip Report December 2022

What Similan liveaboards Do You Recommend?

There are a quite a few liveaboards operating in the Similan Islands now that Thailand has re-opened after the Covid-19 pandemic. My personal current favourite Similan liveaboards as of 2023 are Blue Dolphin (read my in-depth review of the Blue Dolphin liveaboard) and Smiling Seahorse. The Phinisi and The Junk are beautiful boats if you’d prefer the romance of a wooden ship, both owned by the same well-established operator. For more boats similar to these, see Mid Range Similan Island Liveaboards.

There are quite a few budget Similan liveaboards too, but currently there are no luxury boats operating in the Similans. You can see a complete list of Similan Liveaboards to browse and compare prices and departure schedules.

Recommended Similan Liveaboards October 2025 to May 2026

Blue Dolphin Liveaboard

A mid-range liveaboard with 7 cabins for 16 people. Check availability and pricing

The Phinisi Liveaboard

A Similan mid-range liveaboard with 7 cabins for 18 people.Check availability and pricing

Smiling Seahorse Liveaboard

A mid-range liveaboard with 8 cabins for 16 people. Check availability and pricing

The Junk Liveaboard

A mid-range liveaboard with 6 cabins for 18 people. Check availability and pricing

How Many People Are Typically On A Similan liveaboard?

Some boats, like Blue Dolphin and Smiling Seahorse, operate with a maximum of 16 guests. Other boats operate with 24 guests which makes the boat cheaper but a lot more crowded. It makes a difference to the quality of your trip so do check your chosen liveaboard’s maximum capacity.

What’s Included In A Similan liveaboard

Your accommodation, obviously, as you’re living on board. Accommodation choices are typically a quad cabin with 4 bunks or a double cabin with double bed or twin bed. If you’re travelling single, you can share or pay a single supplement to have the cabin to yourself.
All your dives with a guide; dive tank; weight and belts. Hiring dive gear is usually extra, as is diving with Nitrox. You’ll need wetsuits, boots, fins, mask, a BCD and a regulator.
All your food is included – breakfast, lunch, dinner and snacks. Water is free along with electrolytes which are important to drink to avoid cramp.
Some boats include unlimited free soft drinks – Coke etc. Some charge for soft drinks. All boats charge for beer and wine.
– Some boats include free coffee from a real coffee machine on board, some charge for it, some just have instant coffee powder.
Marine Park fees are NOT included – see below.

Are The Similan Islands A National Park?

Yes, they are. The Similan Islands National Park comprises of the nine Similan Islands themselves and Koh Bon and Koh Tachai further north.

Richelieu Rock is part of the Surin Islands National Park, which is even further north.

As such, liveaboard guests have to pay two sets of National Park fees – one for the Similan Islands park and one for the Surin Islands Park. These fees are 2300 Thai Baht in total per person for a four day liveaboard. The fees are not included in any quoted liveaboard price – they’re always an extra. It’s important to remember to bring the fees in Thai Baht cash as the boat captain has to hand it over to the Similan park rangers – there’s no ATM or credit cards!

Hard coral circles, Ao Suthep © chris@divehappy.com

How Much Time Should I Spend In The Similan Islands?

A standard Similans liveaboard is 4 days and 4 nights, so this is the default time many people spend in the Similan Islands. Some enthusiastic divers do back to back trips, repeating the same itinerary, just to see what will show up again.

Alternatively you can spend just one day in the Similan Islands by doing a speedboat day trip.

If you want to stay in the islands, then heading to the Surin Islands which are further north of Richelieu Rock is the place to go

The Surin Islands have some spectacular shallow hard coral gardens which are ideal for snorkelers – Ao Suthep bay is particularly great.

Where Are The Similan Islands Located In Thailand?

The Similan Islands are located in the south of Thailand in the Andaman Sea, north of Phuket and south of Myanmar’s Mergui Archipelago. You can see the Similan Islands and the Surin Islands on the Google map below – zoom in for more details on each island

How To Get To The Similan Islands?

The two main ways to get to the Similan Islands are either on a Similan liveaboard or by speedboat for a day trip.

Speedboats depart every day during high season (November to April). There are speedboats specifically for divers and speedboats for snorkelers and daytrippers who simply want to see the beautiful pristine beaches.

What Should I Pack For A Dive Trip to the Similan Islands?

See our comprehensive liveaboard packing list to make sure you don’t forget anything.

What Dive Insurance Do I Need For Thailand ?

Considering travel insurance for your trip? World Nomads offers coverage for more than 150 adventure activities including scuba diving, as well as emergency medical, lost luggage, trip cancellation and more.

If you are planning to do a lot of diving over the course of a year, it’s best to get a dedicated annual scuba diving insurance policy from Divers Alert Network.

Where To Stay Before And After A Similan Islands Liveaboard?

Arriving For Your Similan Liveaboard

Similan liveaboards usually depart from Tapla Mu pier in the evening of the first day of the trip.

Tapla Mu pier is located a 1 hour drive north of Phuket Airport near to the resort town of Khao Lak.

It’s easy to fly into Phuket Airport and go to the liveaboard operator’s dive shop in Khao Lak where you can finalise any paperwork, have a stroll around the town and have an early dinner if needed. The operator will transfer you from Khao Lak to the pier.

Alternatively, you can go from the Phuket Airport direct to the boat. Just check with your liveaboard operator so they know where to find you.

If you’ve got more time, you can arrive a few days earlier and spend some time in Phuket or Khao Lak.

Phuket is a big island with a lot of different beaches to choose from – see Travelhappy’s Phuket Quick Guide for an overview to get orientated.

Khao Lak town is quieter than Phuket and has three main beaches – see this Khao Lak Quick Guide.

For the taxi from Phuket Airport to Khao Lak, either ask your liveaboard operator to organise one for you, or book a taxi online so there’s a driver waiting to meet you.

Where To Stay After Your Similan Liveaboard

After the liveaboard, you’ll typically need to stay one night before you can fly (you have to be out of the water for 24 hours before flying). Liveaboards typically get back to port around 3 to 4 pm, and will organise taxi transport for you to your chosen hotel. You’ll be asked for your hotel address during the trip so they can organise the taxi for you.

There are hundreds of accommodation options for all budgets – check pricing and availability for Phuket hotels and Khao Lak hotels.

If you want to stay right by Phuket Airport so you can easily leave the next day, the Sixteenth and BS Hotel are both decent cheap hotels nearby that offer a free airport drop-off. Both hotels are only a few minutes walk from Nai Yang beach where there’s numerous other resorts to choose from.

Destination

Check-in date

Wed 18 Jun 2025

Check-out date

Thu 19 Jun 2025

You can also stay in Khao Lak and get a taxi the following morning to Phuket Airport. Just be sure to allow an hour and a half at least for the journey, just in case there’s a lot of traffic.

Ruk Cosy is a great budget place to stay in Khao Lak – cheap, comfortable and a very friendly, with a helpful owner who speaks fluent English. There are plenty of other Khao Lak hotel choices, with many of them right on or near to the beach.

When To Dive The Similan Islands? What’s The Best Time Of Year?

The Similan Islands National Park is open from mid October to mid May. The weather at the beginning and end of the season can be variable. My personal favourite time to go is the last two weeks of April, after the Songkran holiday. It’s usually quieter with less divers around and conditions are great. You can’t dive in the Similan Islands between mid May to mid October – the national park is closed and so it’s illegal to enter it.

Are The Similan Islands Safe For Travelers?

Yes, the Similans are very safe provided you follow all safety procedures during diving and especially on the surface. Always deploy a Surface Market Buoy when you come up from a dive so you can be seen by any boats around you.

What Topside Things Are There To Do In The Similan Islands?

The Similan Islands are a protected natural park, so hanging out on the beach, walking up to the viewpoint over Donald Duck bay, admiring the view and going snorkelling and scuba diving are the main activities.

As of 2023, you cannot stay on the Similan Islands. There used to be a couple of campsites on Koh Miang and Koh Tachai but these have been closed down to protect the islands.

You can still stay on the Surin Islands in basic campsite accommodation, although most visitors do Surin Islands snorkelling day trips.

Are The Surin Islands Separate From The Similan Islands?

Yes. The Surin Islands are another group of islands further north of Richelieu Rock. Richelieu Rock and the Surin Islands belong to the Surin Islands National Park. Koh Tachai, Koh Bon and the Similan Islands belong to the Similan Islands national park.

A typical Similan liveaboard will enter the Surin Islands national park to dive Richelieu Rock and may also visit the Surin Islands themselves. There is some fantastic hard coral gardens in several areas of the Surin Islands, notably Ao Suthep. These gardens are very shallow and ideal for snorkelling.

How Far In Advance Should I Book A Similan liveaboard?

If you’re on a tight schedule, then you should look to book several months in advance as the more popular boats are often full weeks before departure. You can check Similan liveaboard availability for your chosen dates on Liveaboard.com.

As people have begun to travel again after the Covid-19 pandemic, Similan liveaboards have become very busy as there are less boats operating than before the pandemic.

If you are travelling long-term and have more flexibility, you can see if you can get a last minute liveaboard deal.

Flights between Bangkok and Phuket run numerous times a day, but also can get expensive if left to the last minute.

Similan Liveaboards Overview

Upcoming Similan Liveaboard Availability and Pricing

Check availability and pricing for all Similan Islands liveaboards departing in

(The Similan National Park is closed from mid May to mid October each year)

Similan Liveaboards Trip Reports

Photos from each of the Similan liveaboard trips I've been on over the years.

Similan Islands Liveaboard Trip Report December 2022