Liveaboard Diving in Koh Tachai

What To Expect On A Koh Tachai Liveaboard

Liveaboards to Koh Tachai usually visit this area on a Similan Islands itinerary on their way to Richelieu Rock. It's only 12 square kilometers in size and is located northwest of Similan Islands National Park; it lies between the Similan and Surin Islands. An idyllic location in the Andaman Sea, this small uninhabited island comprises a lush rainforest, stunning white sandy beaches, and crystal clear waters. Relatively untouched Koh Tachai is still unspoiled and worth the visit on your liveaboard dive cruise. Below the surface, some other visitors include whale sharks, manta rays, leopard sharks, and Napoleon wrasse, to name just a few. The waters around the island are quite shallow towards the shore, then drop off suddenly to depths of 70 meters. These drop-offs act as a barrier and protect the island, and its rich waters offer excellent snorkeling.

What You Can See

There are two great dive sites at Koh Tachai: the plateau to the south and the eastern reef. The sheltered, shallower waters off the eastern coast make for good night dives. Most liveaboards will moor here for the night.

Koh Tachai plateau, about 1km southeast of the island, is so named because it is ringed by a ridge-like coral plateau crowned with hard corals, gorgonian sea fans line the scattered boulders, sloping from 12 - 35 m to the sandy bottom where leopard and nurse sharks lie peacefully undisturbed. Groups of snapper lurking on the top ledges, octopus hiding amongst the corals, under which red-banded cleaner shrimp work tirelessly. It is best to pay close attention to the divemaster's brief as this site can sometimes be challenging, although the swim-throughs provide shelter from the strong currents. There is a decent line from a buoy on the south side, helping the diver to descend in sometimes strong surface currents. This site is for the more experienced diver. Towards the end of the dive, you may see coral-eating Hawksbill turtles, groups of batfish, or even the banded sea snake lurking near the mooring line upon your ascent. Keep an eye out for the odd Napoleon wrasse patrolling the area.

Koh Tachai pinnacle is usually done as a drift dive, and here, the currents bring high levels of plankton during February - April, and in turn, the larger pelagics feeding on them, such as the Manta Ray and Whale Shark. The strong currents enable the barracudas, trevallies, and sharks to hunt easily for smaller prey. Early morning dives can wake you up from your slumber quite quickly as it can sometimes be a feeding frenzy, and you may not know where to look as there are so many fish. Visibility varies on the month and the amount of plankton in the water, between 10-30m. If the larger pelagics are not shown, then be on the lookout for the macro life. Small frogfish and nudibranchs are known to grace these waters.

An impressive underwater topography mixed with diverse marine life makes Koh Tachai a must for Surin or Similan cruises.

Getting There

The best way to get to Koh Tachai is on a Thailand liveaboard trip to the Similan or Surin Islands, which will depart from either Phuket or Khao Lak. Further from Phuket than from Khao Lak (200 km north of Phuket and 80 km northwest of Khao Lak), it is worth checking what port you prefer to depart from. Khao Lak is about 100km north of Phuket and can be reached overland. Please check your itinerary before purchasing flight tickets. There are international flights into Phuket and domestic flights from Bangkok to Phuket. Reachable from Khao Lak in one hour, you may find other day boats in the area.


Koh Tachai Diving Reviews

  • 9.1 Superb
  • 277 Verified Reviews
  • 9.2 Superb
  • Thomas M
  • United States United States

Good manta spotting, excellent visbility

Diving Koh Tachai in February on the White Manta

  • 9.6 Exceptional
  • Raven J
  • United States United States

Excellent. We got to see a giant manta, schools of barracuda, and a school of mating parrot fish.

Diving Koh Tachai in November on the Deep Andaman Queen

  • 9.2 Superb
  • Ginae L
  • United States United States

Poor visibility, otherwise great

Diving Koh Tachai in January on the Manta Queen 8

  • 10.0 Exceptional
  • chad F
  • United States United States

Whale Shark and mantas !!!!

Diving Koh Tachai in February on the DiveRACE Class E

  • 9.6 Exceptional
  • Richard T
  • United States United States

Viz was not the best but meant lot of Sea Life

Diving Koh Tachai in February on the DiveRACE Class E

  • 6.8 Review score
  • Jeffery C
  • United States United States

Second dive was good, despite strong currents and poor viz. Spotted a guitar shark on the sea floor and tons of moray eels

Diving Koh Tachai in December on the Camic

  • 10.0 Exceptional
  • Dan P
  • United States United States

Enjoyed the good visibility around the twin pinnacles.

Diving Koh Tachai in March on the The Junk

  • 9.6 Exceptional
  • Dylan S
  • United States United States

Great, but strong currents

Diving Koh Tachai in December on the Dolphin Queen

  • 10.0 Exceptional
  • John K
  • United States United States

One beautiful dive site after another. Hard to choose the best.

Diving Koh Tachai in December on the Bavaria

  • 10.0 Exceptional
  • Cory S
  • United States United States

Really busy. Boats overhead the whole time.

Diving Koh Tachai in December on the Sawasdee Fasai

  • 9.2 Superb
  • Cameron S
  • United States United States

We were unlucky on our dives and didn't see any large marine life. Unfortunately, most of the reefs in this area of Thailand are bleached, so without sea life the dives are a little disappointing. We know of other divers that have seen a lot more and that would have made our dives better - we may have just been unlucky.

Diving Koh Tachai in January on the Andaman

  • 9.6 Exceptional
  • William Q
  • United States United States

We dove a couple of times at Koh Bon, which had abundant marine life and colorful coral.

Diving Koh Tachai in January on the Sawasdee Fasai

  • 6.0 Review score
  • Fred Louis G
  • United States United States

Unfortunately, I dived without current. 😕

Diving Koh Tachai in January on the Giamani

  • 9.2 Superb
  • William R
  • United States United States

Three dives here and one was a bit challenging with the current. Supposedly it brings larger fish because of it

Diving Koh Tachai in February on the Blue Dolphin

  • 8.0 Very good
  • RAVI T
  • United States United States

Great site and clear visibility.

Diving Koh Tachai in February on the Bavaria

  • 9.2 Superb
  • ERIC R
  • United States United States

There is always something new to find and photograph.

Diving Koh Tachai in March on the DiveRACE Class E

  • 8.0 Very good
  • Andrew F
  • United States United States

Also great, some lovely coral formations along with a few great pelagics.

Diving Koh Tachai in December on the Sawasdee Fasai

  • 8.0 Very good
  • James C
  • United States United States

Like a Coral Graveysrd, but still a great deal of Coral & Fans, enjoyed the dive.

Diving Koh Tachai in February on the Peterpan

  • 9.6 Exceptional
  • Johnathon W
  • United States United States

A lot of current but great!

Diving Koh Tachai in February on the Bavaria

  • 8.8 Fabulous
  • Scott H
  • Switzerland Switzerland

Water warm and visibility was very good. Many dive boats are around at the same time which does detract from the great dive location.

Diving Koh Tachai in December on the White Manta

  • 8.8 Fabulous
  • Erica W
  • Canada Canada

The water so warm no wetsuit needed and the fish were plentiful

Diving Koh Tachai in January on the Pawara

  • 9.6 Exceptional
  • Won Jeung L
  • South Korea South Korea

Sometimes strong current and surge, but that made the diving more interesting. FIsh and human struggling at the same time.

Diving Koh Tachai in November on the Sawasdee Fasai

  • 9.6 Exceptional
  • Giorgio B
  • Italy Italy

The second best spot, where we spent two dives, totally worth. Comparing to Richelieu Rock, that’s more suitable for big fishes. A wonderful Manta Ray spotted from very close.

Diving Koh Tachai in November on the Deep Andaman Queen

  • 9.2 Superb
  • Kerstin L
  • Sweden Sweden

The Dome was visited three times and every time it was different things to see. Good experience!

Diving Koh Tachai in November on the Manta Queen 1

  • 9.2 Superb
  • Ozlem I
  • United Kingdom United Kingdom

It was little bit difficult with current but I believed I improved my skills as well. They know what they are doing it ... our instructors are very good.

Diving Koh Tachai in November on the Manta Queen 3

  • 9.6 Exceptional
  • Kathryn C
  • New Zealand New Zealand

Beautiful and similar to the other dive sites in the area in terms of life.

Diving Koh Tachai in December on the The Junk

  • 9.6 Exceptional
  • Simon V
  • Belgium Belgium

Really nice diving, beautiful reefs

Diving Koh Tachai in December on the The Junk

  • 9.6 Exceptional
  • Krasimir S
  • Bulgaria Bulgaria

Excellent diving site. We experinced a bit of current.

Diving Koh Tachai in December on the The Junk

  • 9.6 Exceptional
  • Thomas S
  • New Zealand New Zealand

Great, although experienced strong currents

Diving Koh Tachai in December on the Manta Queen 8

  • 9.2 Superb
  • Vikram N
  • India India

Koh Tachai dives were good though visibility was variable. At Koh Bon things were better and even saw a whale shark!

Diving Koh Tachai in January on the Deep Andaman Queen

  • 9.2 Superb
  • Truls P
  • Norway Norway

We had awesome dives here, saw the tiger shark and had great visibility, without too much current.

Diving Koh Tachai in January on the Similan Explorer

  • 9.2 Superb
  • Mariano O
  • Belgium Belgium

Healthy coral and plenty of fish

Diving Koh Tachai in January on the Manta Queen 1

  • 10.0 Exceptional
  • Myeongjin K
  • South Korea South Korea

다양한 생물들이 살아서 좋지만 시야가 그리 좋지 않다

Diving Koh Tachai in January on the Sawasdee Fasai

  • 10.0 Exceptional
  • Joshua K
  • Singapore Singapore

Huge volume marine life! Amazing to watch. Must visit

Diving Koh Tachai in January on the Dolphin Queen

  • 9.6 Exceptional
  • Mathieu B
  • Canada Canada

Challenging (current) but we loved it!

Diving Koh Tachai in January on the Deep Andaman Queen

  • 10.0 Exceptional
  • Tomaz J
  • Slovenia Slovenia

Great spot, but a little bit of current

Diving Koh Tachai in January on the The Junk

  • 9.2 Superb
  • julien T
  • Switzerland Switzerland

Great diving, not the best spot but pretty nice.

Diving Koh Tachai in January on the Dolphin Queen

  • 10.0 Exceptional
  • Dirk D
  • Germany Germany

Many fish’s and colour full Dive sides

Diving Koh Tachai in January on the Merdeka 1

  • 8.4 Very good
  • Suk Kyoung S
  • Canada Canada

Tachai with great marin life but not so good visibility

Diving Koh Tachai in February on the Sawasdee Fasai

  • 9.2 Superb
  • E****d C
  • Australia Australia

Strong current so less enjoyable.

Diving Koh Tachai in February on the The Junk

  • 8.0 Very good
  • RYAN C
  • Canada Canada

This was my personal favorite of the trip. The visibility was better here than any other place we went and there was an abundance of active marine life.

Diving Koh Tachai in February on the Manta Queen 5

  • 10.0 Exceptional
  • James M
  • Canada Canada

Fantastic! Got to see some big fish!

Diving Koh Tachai in February on the Manta Queen 3

  • 7.2 Good
  • Kai-Oliver G
  • Germany Germany

Koh Bon and Koh Tachai were the best from our trip. Sadly we had only 1 day there.

Diving Koh Tachai in February on the Manta Queen 8

  • 9.2 Superb
  • Sherri F
  • Australia Australia

The dome was great. We wish we had done a true ‘night dive’ there. We got out of the water before the sun had even set!!!

Diving Koh Tachai in February on the Manta Queen 2

  • 9.6 Exceptional
  • Pierre B
  • France France

A nice dive. Not the best of the trip but very pleasant!

Diving Koh Tachai in February on the The Junk

  • 8.8 Fabulous
  • Eric L
  • Canada Canada

Mantas galore. How can you ask for any better. Blessed by God.

Diving Koh Tachai in March on the Manta Queen 7

  • 9.2 Superb
  • Tobias T
  • United Kingdom United Kingdom

Amazing - WHALE SHARKS AND MANTAS

Diving Koh Tachai in March on the Manta Queen 3

  • 9.6 Exceptional
  • Alan G
  • New Zealand New Zealand

The pinnacle was very cool lots of stuff to view, the barracuda balls were amazing

Diving Koh Tachai in March on the Deep Andaman Queen

  • 9.2 Superb
  • Caroline F
  • United Kingdom United Kingdom

Koh Tacha for me was a little scary a lot of current which I'm not used to, but again beautiful diving.

Diving Koh Tachai in April on the Manta Queen 5

  • 8.0 Very good
  • Alba R
  • Spain Spain

Good diving. Relaxing drift dives.

Diving Koh Tachai in November on the Bavaria

  • 10.0 Exceptional
  • Sherri L
  • Canada Canada

Amazing. Saw an eagle ray.

Diving Koh Tachai in February on the Sawasdee Fasai

  • 9.6 Exceptional
  • Maurice V
  • Netherlands Netherlands

We had a strong current, but luckily there are enough places behind rocks to shelter and relax. There was an impressive school of big chevron barracuda's.

Diving Koh Tachai in February on the Sawasdee Fasai

  • 8.0 Very good
  • Miklos H
  • Hungary Hungary

Schools of batfish, trevallies

Diving Koh Tachai in May on the Manta Queen 2

  • 9.2 Superb
  • Sharangdev M
  • India India

Koh Tachai was great, strong currents on both the dives there. Koh Bon was very nice too

Diving Koh Tachai in May on the Sawasdee Fasai

  • 8.0 Very good
  • Lee F
  • Australia Australia

The best site but we only did a sunset and very early morning dive there & never saw it at it’s best.

Diving Koh Tachai in October on the Sawasdee Fasai

  • 8.4 Very good
  • Dmitrij Z
  • Germany Germany

Challenging due to strong currents, but rewarding

Diving Koh Tachai in October on the Manta Queen 7

  • 9.6 Exceptional
  • Jan S
  • Austria Austria

big blue experience going in. A bit challenging because of the current. Amazing coral.

Diving Koh Tachai in October on the Camic

  • 9.6 Exceptional
  • Felix K
  • Germany Germany

Cool pinacle, sometimes strong currents, possible to See sharks

Diving Koh Tachai in November on the Marco Polo

  • 9.2 Superb
  • Laurence B
  • United Kingdom United Kingdom

Lots of fish, wreck effective an artificial reef, so manage expectations if you want a wreck dive

Diving Koh Tachai in November on the DiveRACE Class E

  • 10.0 Exceptional
  • Erica M
  • Australia Australia

Nice night dive with rich sea life and interesting rock formations.

Diving Koh Tachai in November on the Camic

  • 9.2 Superb
  • Siew Cheng W
  • Singapore Singapore

Experienced stronger current but fun.

Diving Koh Tachai in November on the Andaman

  • 8.8 Fabulous
  • Julien L
  • France France

2 awesome dives there, Moray Eels, Garden eels, Giant Trevalies, amongst great life to see there

Diving Koh Tachai in November on the Camic

  • 10.0 Exceptional
  • Wei-Yi L
  • United Kingdom United Kingdom

Great dive location with healthy corals. Great dive sites with much to see and explore.

Diving Koh Tachai in December on the DiveRACE Class E

  • 10.0 Exceptional
  • Ben C
  • Canada Canada

The Dome was a very cool site with lots of cool wildlife.

Diving Koh Tachai in December on the Manta Queen 2

  • 8.8 Fabulous
  • Martin N
  • Ecuador Ecuador

Great dive site. Saw plenty of life.

Diving Koh Tachai in January on the Manta Queen 7

  • 8.8 Fabulous
  • Elisabeth U
  • Austria Austria

Great, snakes, guitarsharks

Diving Koh Tachai in January on the Manta Queen 7

  • 8.0 Very good
  • Anders R
  • Sweden Sweden

No mantas or wale shark this time but overall according to my expectations.

Diving Koh Tachai in January on the Manta Queen 2

  • 9.6 Exceptional
  • Andrea B
  • Argentina Argentina

Another Great Spot, especially the Dome

Diving Koh Tachai in January on the Manta Queen 2

  • 9.6 Exceptional
  • Yi Yun C
  • Taiwan Taiwan

It’s cool. A lot of different marine lives.

Diving Koh Tachai in January on the Manta Queen 2

  • 9.6 Exceptional
  • DIANE J
  • United Kingdom United Kingdom

reefs had good coral and sea life, no pelagics

Diving Koh Tachai in February on the Bavaria

  • 10.0 Exceptional
  • David T
  • United Kingdom United Kingdom

Good site with a good variety of smaller fish life.

Diving Koh Tachai in February on the Sawasdee Fasai

  • 8.0 Very good
  • Bryanne P
  • Canada Canada

Amazing visibility and marine life

Diving Koh Tachai in February on the Manta Queen 7

  • 9.2 Superb
  • Sunny A
  • Singapore Singapore

Clear water and great sightings

Diving Koh Tachai in February on the Marco Polo

  • 5.6 Review score
  • Henrik Qvistgaard R
  • Denmark Denmark

We had strong current, so the pinnacle was hard to dive, and not really worth it, but would be great in calmer water

Diving Koh Tachai in March on the Dolphin Queen

  • 9.6 Exceptional
  • Anthony G
  • Australia Australia

Lots of fish and great visibility

Diving Koh Tachai in March on the Manta Queen 1

  • 9.2 Superb
  • Jonathan S
  • United Kingdom United Kingdom

My favorite dive site is Koh Tachai, its a challenging site with potential strong current but it has everything + decent viz.

Diving Koh Tachai in March on the DiveRACE Class E

  • 9.6 Exceptional
  • HANEUL K
  • South Korea South Korea

a lot of sting ray and saw a big black tip shark

Diving Koh Tachai in March on the Pawara

  • 10.0 Exceptional
  • Sin Man Carol H
  • Hong Kong Hong Kong

Exceptional, with clear water and variety of marine life.

Diving Koh Tachai in April on the Andaman

  • 8.8 Fabulous
  • Yolanda T
  • Hong Kong Hong Kong

Strong current on one of the dives, we had to abort early. But this was where we saw manta rays!!

Diving Koh Tachai in April on the Sawasdee Fasai

  • 9.6 Exceptional
  • Karan S
  • Australia Australia

Great, second favourite dive site after Richelieu Rock, teeming with life and fun currents.

Diving Koh Tachai in April on the Manta Queen 3

  • 9.6 Exceptional
  • Rishir K
  • India India

There seemed to be a thermocline because of the currents

Diving Koh Tachai in April on the Dolphin Queen

  • 9.6 Exceptional
  • Lai Shan L
  • Hong Kong Hong Kong

Sometimes tough due to current.

Diving Koh Tachai in April on the Pawara

  • 8.8 Fabulous
  • Po Ling L
  • Malaysia Malaysia

Strong current and not very lucky

Diving Koh Tachai in May on the Dolphin Queen

  • 8.4 Very good
  • . Chuiki J
  • United Kingdom United Kingdom

Beautiful and riding the currents was fun.

Diving Koh Tachai in May on the Andaman

  • 8.8 Fabulous
  • Sin Tung Candice L
  • Hong Kong Hong Kong

Shallow reef but a good chance of spotting large schools of fish.

Diving Koh Tachai in October on the Manta Queen 7

  • 9.6 Exceptional
  • Sander V
  • Netherlands Netherlands

Loved it, saw a couple of Guitar Sharks and Jenkins & marble rays.

Diving Koh Tachai in December on the Sea World 1

  • 9.6 Exceptional
  • Alwin O
  • Netherlands Netherlands

Regular for an experienced diver, who’s obviously looking for Richelieu quality diving sites.

Diving Koh Tachai in December on the Dolphin Queen

  • 8.4 Very good
  • Kai S
  • Germany Germany

lots of fish, nice sites, poor visibility

Diving Koh Tachai in December on the Explorer

  • 10.0 Exceptional
  • Katie O
  • United Kingdom United Kingdom

Stunning diving, so much life here and less busy than Richelieu.

Diving Koh Tachai in December on the DiveRACE Class E

  • 9.2 Superb
  • Omar A
  • Saudi Arabia Saudi Arabia

I didn’t like it at all. The current was so strong and the viability was very bad to be honest.

Diving Koh Tachai in January on the Explorer

  • 6.4 Review score
  • Kiyoshi N
  • Japan Japan

Unfortunately conditions were not good at all.

Diving Koh Tachai in January on the Sawasdee Fasai

  • 8.8 Fabulous
  • Jeongmin H
  • South Korea South Korea

The current was so strong in the first dive that it was difficult, but it was a rich place to see.

Diving Koh Tachai in January on the DiveRACE Class E

  • 10.0 Exceptional
  • Tim G
  • Switzerland Switzerland

About 10m visibility only but lots of fish schools

Diving Koh Tachai in January on the DiveRACE Class E

  • 10.0 Exceptional
  • Ulf I
  • Germany Germany

Big schools of fish. What diving way away from shore can offer

Diving Koh Tachai in January on the Blue Dolphin

  • 10.0 Exceptional
  • Sabrina M
  • Italy Italy

Amazing dive with manta rays!

Diving Koh Tachai in January on the Blue Dolphin

  • 8.8 Fabulous
  • Lauren E
  • United Kingdom United Kingdom

Lots of current here too. Night dive on the reef was amazing

Diving Koh Tachai in February on the Gentle Giant

  • 9.2 Superb
  • Jerome B
  • United Kingdom United Kingdom

Depending on the current, can be great or challenging

Diving Koh Tachai in February on the Sea World 1

  • 10.0 Exceptional
  • Veronica R
  • Norway Norway

Amazing, a lot of life and great dives

Diving Koh Tachai in February on the Sawasdee Fasai

  • 10.0 Exceptional
  • peggy M
  • Germany Germany

Tachai Pinnacle or Batfish rock was stunning as well with tge chance to see some big stuff whirling around.

Diving Koh Tachai in February on the Explorer

  • 10.0 Exceptional
  • Andres G
  • United Kingdom United Kingdom

Another great diving site. Very different from the other ones but also beautiful with the white sand.

Diving Koh Tachai in February on the Dolphin Queen