...Highlights: whale sharks, turtles, schooling fish/big pelagics...
...Diving environment: beginner divers, advanced divers, very popular...
'Turtle Island' (as the name 'Koh Tao' means in English) has long been a magnet for backpackers and traveller types who want learn about scuba diving. The many shallow bays are used to certify more PADI student divers than anywhere else in the world outside of Australia.
The island is located to the north of Samui and Koh Phangan in the Gulf of Thailand. There are highly affordable day trips to the many easy dive sites dotted around Koh Tao's coastline.
There are also a couple of offshore pinnacles - Chumphon and South West Pinnacle - which offer more challenging dives and the opportunity to encounter bigger fish, as well as diving with whale sharks when in season. Chumphon Pinnacle in particular has gained a favourable reputation as being one of the best and most popular dive locations in the Gulf of Thailand.
In recent years the diving in Koh Tao has been enhanced by the deliberate sinking of 2 ships to form wreck dives for the visitors here. MY Trident was sunk in 2010 and lies at 36m to the south of Shark Island. It is suitable for advanced divers. HTMS Sattakut was sunk in 2011 in 30m near Hin Pee Wee off the east coast of Koh Tao. It is a bigger ship and suitable for intermediate divers. Both wrecks have already become crowded with crustaceans and fish that use the recesses of the vessels as a safe refuge.
Ao Leuk - This shallow bay's easy, relaxing diving is strongly recommend for beginners or for scuba divers that haven't got wet for a while. The Thai name means 'Deep Bay' which is something of a misnomer since it is one of the shallowest of Koh Tao's dive sites, with its sandy bottom allowing a maximum depth of only 12-14 metres. There are a surprising amount of reef fish for such a location, such as butterflyfish and angelfish, schools of juvenile yellowtail barracuda and turtles. Show more
All the famous dive sites of Koh Tao can be visited on day trips from Koh Samui Island. For more information on these options, and all the other travel information you might need to visit Samui and the Gulf of Thailand, read our Koh Samui day trips section.
The high speed catamaran departs every morning, normally with small groups of divers. You will normally return at 5:00 pm in the early afternoon.
You can book these dive day trips separately, or combine them with accommodation at one of our recommended Koh Samui resorts.
The dive sites around Koh Tao can be visited throughout the year. The water is an average temperature of 28-29°C. However, the best season for optimum conditions is from March to September, with the busiest months being July and August. The weather during this period is warm and usually sunny, offering the best conditions for diving, especially in terms of underwater visibility.
Monsoon winds reduce visibility from October to November, and sea swells can be present. However, these are rarely bad enough to interfere with the running of diving trips. November to February brings rain and winds to Koh Tao so it is not be the best place to be at this time of year.
There is a chance to see big pelagics such as whale sharks, most often in September, but the possibility remains all year around. Titan triggerfish might become aggressive during their breeding season which usually runs from March to April, as they are extremely territorial. The male usually guards the nest against intruders, including scuba divers. They are only following their instincts and divers should avoid getting inside their 'protection zone' (above the nest, as the titans can see upwards).
A positive aspect of Koh Tao is that, being a small island, it is possible to travel around it by boat in less than an hour, visiting the best dive sites that each day has to offer, in terms of conditions and marine sightings. Additionally, Koh Tao's small landmass means that growing rain clouds most often unleash their rains over the larger neighboring islands of Samui, Phangan or the Thai mainland.
Review our map below of Thailand, showing the location of Koh Tao. Here, you will find information on how to get to Koh Samui, from where you will dive at Koh Tao.
Depth: 5 - 35m
Visibility: 5 - 20m
Currents: Usually gentle but can be strong at some sites
Surface conditions: Normally calm, but can be choppy offshore
Water temperature: 27 - 30°C
Experience level: Beginner - intermediate
Number of dive sites: ~15
Recommended length of stay: 5 days