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Best place to see whale sharks in Thailand! [A guide to scuba diving Koh Tao]

Deep into the sea in the Gulf of Thailand sits Koh Tao, a small tropical island isolated by miles and miles of ocean in all directions. Discovered by backpackers and scuba divers nearly 40 years ago it has since exploded in popularity and attracts visitors from all over the world. The main reason to visit? The ocean.

Aerial shot of Koh Tao in the Gulf of Thailand
Reefs, bays & blue sea. What more could you ask for?

Koh Tao is surrounded on all sides by shallow bays, reefs, small islands and pinnacle dive sites. It is in fact one of the most popular spots on the planet for beginners to learn how to scuba dive, quite a feat considering the island is barely 7 by 3km small!

And while there is no shortage of articles written on this beautiful paradise, we're going to focus on whale sharks! Because Koh Tao gets more whale shark observations than anywhere else in the kingdom, and given the shallow depths around the island that means you could potentially get to see one while either scuba diving, snorkeling or free diving! But when is the best time to go?


[November - January]

Koh Tao goes through wet and dry seasons throughout the year. The main monsoon season generally goes from November to January, with various severity. Meaning it can be incredibly rainy and windy some years, and barely get wet in others. It's highly unpredictable and more so in recent years with global climate change, which have seen temperatures here reach new highs, both on land and in the sea. This season usually brings about the coldest temperatures throughout the year, with the ocean cooling down to a chilling 25 or less. You might be laughing, but that's about as bad as we get it here!

[February - May] Next is the dry season, which generally starts towards the end of February and lasts until the middle of May. This is usually when we get the highest temperatures with the ocean reaching temperatures up to 31 degrees and the bays even more so. These months are often excellent for diving, as they usually bring about clear water and whale sharks! But more on that later.
[May - August] Next we get our second wet season, mid May to August. Again these months are highly unpredictable with some years seeing barely any rainfall at all, but we do tend to get winds blowing over from the west coast monsoon. Remember we are talking of a tiny spec of land in the middle of the ocean, and all it takes is the wind changing a few degrees and everything blows down further south.


Finally we get our last season, September to October. While September generally boosts good weather and nice diving conditions, October can be a bit hit and miss. But the ocean is usually calm and conditions great. This is another season where the chances of whale sharks encounters go up.

Whale Shark visits

Believe it or not, we get visited by whale sharks throughout the year! But we have found that there are more of them around during the two dry seasons, Feb – May & Sep – Nov. They tend to arrive in larger numbers at the same time, although they are solitary and are rarely spotted together. Very little scientific data exists on the movements of whale sharks in the Gulf of Thailand. This is not from a lack of trying.

Whale shark spotted at Shark Island, Koh Tao - Thailand
This giant was spotted at Shark Island!

Many conservation centers and research groups have expressed a desire to conduct more research on these majestic animals. But the government authorities makes it very difficult to conduct any such work, as the whale shark is protected by law in all of Thailand.

Conservation programs

Instead we have citizen programs that have been highly successful since their beginning. Underwater photographers of all levels are encouraged to submit images of whale sharks to the Thai Whale Sharks and Koh Tao Whalesharks facebook groups, to help local scientists identify and track individuals through observations. All the data collected here is also shared with international organizations tracking these animals world wide.

Best dive sites to spot them

But before you can help our local scientists out, you probably need to spot a whale shark first! Whale sharks are on the bucket list of most scuba divers in the world. They are the biggest fish in the ocean and divers simply love their gentle nature.

Locally there are some dive sites that see a greater influx of whale sharks than others. They are as follows;

Chumphon Pinnacle

This dive site sits about 12km off the north-west side of the island towards the city of Chumphon on the mainland, hence its name. It's a deep pinnacle starting at 14 meter depth going down towards 40 meters at the deepest. The dive site is beautiful with lots of anemones and corals covering the rocky outcrops, and large schools of various fish species all around the pinnacles. With it's underwater seascape it's a fantastic place to encounter whale sharks, as they tend to swim in closer to the rocks and allow you to observe them next to other marine life.

Sail Rock

Much further away from Koh Tao, and actually much closer to the neighboring island of Koh Phangan sits Sail Rock, a small island pinnacle that surfaces a few meters above sea level, allowing sea birds to use it as a nesting site. Surrounded by deep ocean on all sides it attracts a lot of marine life including our larger sharky friends. Most divers considers this one of the best dive sites in the entire gulf of Thailand, hence it's usually a great dive even without the big spotty fish.

SouthWest Pinnacle

Another great dive site somewhat closer to Koh Tao, this completely submerged site has one large pinnacle with several smaller ones surrounding it. There is even a secret pinnacle located a few minutes swim away, a great place to head off to and explore. There's even been dives where there's a whale shark on the secret pinnacle and not on the main one, so gamble wisely!

Shark Island

Perhaps my favorite local dive site, it is located just a few hundred meters off the south-east coast of Koh Tao in an area with a fair amount of currents. The island boasts large patches of both hard and soft corals, with particularly healthy reef sections in the shallows to the north and deeper off to the south. It's a great place to see whale sharks as there's usually few divers around and the landscape adds interesting compositions for underwater shooters.

Hin Wong Pinnacle

This rarely visited dive site sits to the east of the island and is famous for its currents that usually sweep through the deep rocky formations. It can sometimes reduce visibility and make it quite difficult to explore the entire site, but it is still a beautiful area with nice reefs and a large variety of marine life. Whale shark sightings are more rare, but that can be contributed to the lack of divers that come here.

Green Rock

Green Rock is located at the very northern peak of Koh Nang Yuan, the three islands located just off Koh Tao. It's an interesting dive site, with the largest 'trigger pit' (nesting site for trigger fish) anywhere on the island. Currents can get quite strong here, but the reef is healthy and vibrant. You can also follow a chain of smaller pinnacles leading into the deep, where reef sharks are sometimes spotted.

White Rock & Twins

Quite surprisingly, the two most popular dive sites around Koh Tao actually gets their fair share of whale sharks encounters throughout the year. Nowhere near as often as out on the deeper pinnacles, but still many divers are lucky to have a whale shark pass them while diving here. And considering that these sites are used by many dive schools for open water training dives, there's been a few divers who's had the pleasure of seeing one during the very early start of their diving career.

These aren't the only places to spot whale sharks, but the ones with the best changes. Truth is you could potentially see a whale shark on nearly any dive here. I've even heard of snorkelers seeing them at typical shallow snorkel sights like Chalok Baan Kao and Ao Leuk. So you could truly be in for a wonderful surprise, regardless of whether you scuba dive or snorkel!

To sum it up, whale sharks can be spotted throughout the entire year but if you want a better chance at seeing them come visit around April/May or September/November time. These gentle giants are truly incredible and it's such a magical experience to spend time with them underwater. Thanks for reading, and happy diving!

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