Barracuda tornado, fish stampedes at Richelieu and a manta ray at Koh Bon – this was one of the best Similan liveaboard trips I’ve ever been on.

Manta Ray at Koh Bon, Similan Islands, Thailand, February 2025 © [email protected]
I am not particularly lucky when it comes to scuba diving. How many times have I heard “ooh, you should have been here last week” when I’ve come back from a particularly uninspiring dive.

Longnosed Emperorfish stampeding over barrel sponge with glassfish, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
So on this Similan liveaboard trip in February 2025 it felt like I was finally getting payback for all my patience and near-misses in previous years.

Pook and the jacks, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
To begin at the end, our final dive of the trip at Koh Bon delivered the best finale you could hope for – crystal clear visibility and an oceanic manta ray gliding in from the deep to hang out in Koh Bon bay, the easiest, most current-free spot on the entire dive site. (See more photos of the manta ray at Koh Bon).
Trip Planning Checklist
-
A Similan Islands Liveaboard is typically 4 days and 4 nights long - decide your dates and search for availability on liveaboard.com
-
Also check our Last Minute Liveaboard Deals page for Similan Islands liveaboard discounts.
-
FWIW, I've dived with and like Blue Dolphin, Smiling Seahorse, The Phinisi, Dolphin Queen and Thailand Aggressor.
-
Check times and pricing of flights to Phuket or the bus to Khao Lak with 12go
-
Check my liveaboard packing list to make sure you bring all you need
-
It's compulsory to have diving insurance. World Nomads offers diving insurance as part of their Thailand travel insurance
-
Book a hotel in Khao Lak or Phuket for when you get back from the liveaboard.
-
Decide if you want to stay on in Khao Lak after your trip and go see Khao Sok national park, or head south to explore Phuket
The manta moment followed on from the awesome encounters we’d had over the previous couple of days.

Barracuda Tornado, Koh Tachai, Similan Islands, Thailand, February 2025 © [email protected]
Having already witnessed an epic barracuda tornado on a December 2024 Similan trip, lightning struck twice and it happened again at Koh Tachai on this trip. Hundreds of barracuda circling in perfect visibility at around 10 metres over Koh Tachai pinnacle – it just does not get any better. I’d had some awesome barracuda bait ball encounters before at Tachai but this was on another level. (See more photos of the barracuda tornado at Koh Tachai).

Huge school of fusiliers running around Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
The following day at Richelieu Rock we had more crystal clear visibility which let us see the whole site laid out below us – and some amazing runs of massive schools of fusiliers thousands strong past the rock. Richelieu is notoriously fickle for viz so when it clears it makes it feel even more special.

Longnosed Emperorfish Stampede, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
The long nosed emperorfish were also out in force stampeding over the rock too, flowing around the big barrel sponges and soft corals and any hapless divers that were in the way too.

Snapper and glassfish, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
The glassfish are always at Richelieu Rock, millions of them like a protective silver blanket suspended over the reef. When the sun’s out they gleam over the coral and shape shift around the bigger fish speeding through

Pook and yellow snapper, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
The resident big school of yellow snapper on the inside of the horseshoe were also super active and out en masse.

Jack Tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
Best of all though was the surprise of a big school of jacks forming into a tornado just off the rock out over the flat sandy bottom at 30 metres. While jacks are often seen at Richelieu, I’d never seen them in these numbers or behaving like this. It was even more a surprise after seeing the barracuda the previous day. (See the full set of jack tornado photos).

Longnosed Emperorfish stampede, Christmas Point, Similan Islands, Thailand, February 2025 © [email protected]
On the first couple of days of the liveaboard we enjoyed great dives at several of the Similans’ classic sites. At Christmas Point, amongst the labyrinth of big rocks out of nowhere there had been a stampede of long nosed emperor angel fish which caught us by surprise.

Fan corals and red rocks, Christmas Point, Similan Islands, Thailand, February 2025 © [email protected]
The viz was great at Christmas Point, the sun illuminating the red carpet of coral on the huge rocks shaped by thousands of years of water movement.

Pook with glassfish and soft corals, West of Eden, Similan Islands, Thailand, February 2025 © [email protected]
At West Of Eden, we got to enjoy a different perspective on the site as we dived it in the afternoon whereas we usually see it first thing in the morning as the beginning dive of a trip. There was a lot of activity at Eden and the ledge suffused with soft corals was buzzing with glassfish, making it even prettier than usual.

Huge barrel sponge and blue ringed angel fish, Ao Pakkard, Similan Islands, Thailand, February 2025 © [email protected]
As a pleasant calm interlude between the full on action at Koh Tachai and Richelieu Rock, the early morning dive at Ao Pakkard in the Surin Islands is always a pleasant bob along the reef.

Pipe corals and damselfish, Ao Pakkard, Similan Islands, Thailand, February 2025 © [email protected]
The hard corals here are in fantastic condition, with some huge barrel sponges, plenty of reef fish and coral upon coral piled upon each other.

Damselfish and staghorn coral, Ao Pakkard, Similan Islands, Thailand, February 2025 © [email protected]
The site is shallow and usually without any current, so it’s a perfect start into the day before heading to Richelieu.

Rainbow runners, emperorfish and trevally running together, Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
Incredible to get this variety of experiences and encounters within a four day liveaboard trip. It turns out that if you keep showing up you do actually get to win – sometimes.

Fusiliers over the top of Richelieu Rock, Similan Islands, Thailand, February 2025 © [email protected]
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

Fan corals on the rocks, Boulder City, Similan Islands, Thailand, February 2025 © [email protected]

Grouper, Koh Tachai, Similan Islands, Thailand, February 2025 © [email protected]
2026 Thailand Last Minute Liveaboard Deals
- Sawasdee Fasai - All upcoming 2026 departures! - from $772 - Valid for limited time only (20% OFF)
Similan Islands Dive Sites List
- West Of Eden
- Shark's Fin Reef
- Boulder City
- Christmas Point
- North Point
- Three Trees
- Tuna Wreck and Hideaway Bay
- Koh Bon
- Koh Bon Pinnacle
- Ao Suthep
- Koh Tachai
- Richelieu Rock
Similan Liveaboards Overview
- Luxury Similan Island Liveaboards
- Mid Range Similan Island Liveaboards
- Budget Similan Island Liveaboards
- Last Minute Liveaboard Deals
- Diving The Similan Islands 2026: A Quick Guide
- Similan Islands Dive Sites
- Diving Thailand Guide
Upcoming Similan Liveaboard Availability and Pricing
Check availability and pricing for all Similan Islands liveaboards departing in
- February 2026 | March 2026 | April 2026 | May 2026 | October 2026 | November 2026 | December 2026 | January 2027
(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 9-13 February 2025
- Similan Islands Liveaboard Trip Report 21-25 November 2024
- Similan Islands Liveaboard Trip Report May 2024
- Similan Islands Liveaboard Trip Report 21 - 25 February 2024
- Similan Islands Liveaboard Trip Report 15 - 19 February 2024
- Similan Islands Liveaboard Trip Report December 2023
- Similan Islands Liveaboard Trip Report October 2023
- Similan Islands Liveaboard Trip Report April 2023
- Similan Islands Liveaboard Trip Report February 2023
- Similan Islands Liveaboard Trip Report December 2022
- Similan Islands Liveaboard Trip Report February 2020
- Similan Islands and Myanmar Trip Report March 2015
Similan Dive Sites
Richelieu Rock
Thailand’s best dive site, bar none. A stunning array of soft corals and spectacular stampeding marine life. Read More
Koh Bon
Thailand’s manta ray hotspot, with plenty of other things to see if the mantas don’t show up. Read More
Koh Tachai
Koh Tachai is one of the Similan Islands’ best dive sites but also one of the most volatile. Massive fans, huge schools of fish, maybe manta rays – it’s all to play for. Read More
Boulder City
A dramatic deep water Similan dive site, Boulder City needs the right conditions to explore as it’s exposed to wind and wave from all sides. Read More
Shark’s Fin Reef
A dramatic block of rock rising out of the sand, Shark’s Fin Reef is one of the Similan Islands’ most exciting sites. Read More
Hideaway Bay
Two Similan Islands dive sites in one location, Hideaway Bay and Tuna Wreck can be experienced in a single dive. Read More
North Point
North Point is another of the Similans’ signature big boulder sites, with huge great rocks rising out of the white sand. Read More
Koh Bon Pinnacle
Koh Bon Pinnacle is a deep dive site that feels utterly remote – and where anything could show up out of the blue. Read More
West Of Eden
A big boulder site with spectacular outsize fan corals, beautiful soft corals and the promise of full fish activity, West Of Eden is an archetypal Similan Islands dive site. Read More
Ao Suthep, Surin Islands
Ao Suthep is beautiful hard coral garden in the Surin Islands, often visited by Similan island diving liveaboards and accessible by snorkellers visiting the Surin Islands too. Read More
Three Trees
Three Trees, named after the three trees directly above the dive site on Similan Island 9, is a big wide white sand channel with some awesome corals and fish encounters. Read More
Christmas Point
One of the signature Similan Islands big boulder dive sites, Christmas Point’s huge rocks have been shaped by the tides over hundreds of years. Read More