Diving with Whalesharks

When to see Whalesharks around Koh Tao

Diving Koh Tao – The Best Time To See A Whaleshark

Thailand has lots to offer for the enthusiastic tourist; breathtaking scenery, amazing temples, tasty food, the hustle and bustle of Bangkok and the beautiful Southern Islands.

The smallest and most charming of these three islands is Koh Tao that has a reputation as a world famous scuba diving destination and specifically the most popular place in the world to learn to dive.


The island, popular for its marine life and colourful tropical corals is also famed for frequent sightings of its most famous regular visitor and the fish just about everybody wants to see – the Rhincodon typus, more commonly known as the Whaleshark.

Gentle Giants

Whalesharks can grow up to 15 metres long and weigh over 40 tons making it the world’s largest fish. They are completely harmless to divers and feed on plankton and small fish that are filtered from the ocean by their large mouths as they cruise around the warm waters around countries such as Australia, Mexico, Philippines, Honduras and Thailand.


Around Koh Tao we generally get younger whale sharks. They are gentle and generally very curious and can even be playful with scuba divers. They also make great subjects for underwater videographers and photographers as they are slow swimmers and will stay on a dive site for long periods of time.

The Big Question

The question “Where can I see Whalesharks on Koh Tao?” is a very common one. The easiest answer is in the water! Of course there is an element of luck and although I have snorkeled with Whalesharks this was at a dive site not suitable for snorkeling.

The Whaleshark decided to stay around close to the surface for what seemed like forever! Realistically you need to be diving to be in with a chance.

There have been many lucky student divers that have been able to see these amazing creatures while taking their PADI Open Water course. I once taught a course when we saw Whalesharks on 3 of the 4 open water training dives.


We have had customers making their very first dive as part of a discover scuba dive experience, although this is admittedly rare as normally we see Whalesharks at some of the deeper, outlying dive sites that aren’t suitable for DSDs.

Realistically you would need to be a certified PADI Open Water diver at a minimum to dive the sites Whalesharks are most often seen such as Chumphon Pinnacles or South West and these sites are best enjoyed by Advanced open water divers.

Being an advanced diver gives you better flexibility of depth as you can dive to 30m that enables you to fully enjoy the more famous dive sites. Saying this I’ve seen Whalesharks at sites such as White Rock that we often use for open water training dives too!

The can be no guarantee of seeing a whaleshark as when you are diving in the ocean it is such a vast space but the more you dive the more chance you have of seeing the biggest fish in the sea.

So which dive site exactly?

The most common dive sites we see these graceful creatures are at Sail Rock, Southwest Pinnacle and Chumphon Pinnacle, all deep dive sites located a short distance from the island.

These are also Koh Tao’s most popular dive sites in part due to the diversity of marine life – not just Whalesharks – that live in and around these sites. It is common to dive with large schools of Barracuda and Trevally and spot giant groupers in the shadows close to the granite pinnacles of these sites.


There is also a huge array of colourful marine life commonly associated with the tropical waters.

Two other dive sites popular with Whalesharks are Shark Island, located off the south west of Koh Tao and Hin Wong Pinnacle over on the east side of the island. Again both these dive sites are classed as advanced sites and can often be two of Koh Tao’s more challenging dives due to currents.

Occasionally Whalesharks are spotted at White Rock and Twins, two of Koh Tao’s dive sites popular for PADI Open Water Course training dives. Both of these dive sites are located off the west cost of Koh Tao with Twins one of the 4 popular sites located just off Koh Nang Yuan Island.

Even if you don’t see a whale shark on white rock and twins you are very likely to see one of the many sea turtles that have made their home on these dive sites.

When is Whaleshark Season

The million-dollar question – well for scuba divers visiting Koh Tao anyway!

Many dive destinations where Whalesharks visit and migrate to have a specific time of the year that is most common to spot Whalesharks. Here on Koh Tao we are lucky enough to see these amazing creatures all year round.

Although there are specific times of year when visiting Whalesharks are more common to our dive sites, they can turn up out of the deep blue at any time!

Generally speaking there are two periods of the year when spotting these fantastic creatures seems to be more common than the rest of the year.

The first period is March / April / May, this actually coincides with the best time to dive Koh Tao as the weather is usually excellent, nice and hot with stunning sunsets to enjoy at the end of the day.


The beautiful sunny days with little or no wind create excellent diving conditions and we get extra whalesharks who also seem to enjoy these conditions too!

This year in March and May we have experienced something of a whaleshark bonanza with multiple dive trips seeing multiple whalesharks, at multiple dive sites – all at the same time!

The second time of the year where Whalesharks are more frequent is October / November / early December. As the rainy season soaks Northern Thailand a lot of nutrients gets washed into the water creating plenty of micro-algae that in turn attracts Whalesharks.

The deep dive sites of Chumphon and Sail Rock see a lot of extra activity especially at this time of year from our favourite big spotty fish.

How to behave around a Whaleshark

It is important to remember that while sharing water with these amazing creatures, it is a once in a lifetime experience and ticks off a bucket list experience for most people. It is very important to treat these creatures with the utmost respect.

Here on Koh Tao we adhere to Whaleshark standards and guidelines that ensure we do not endanger, harm or harass the fish. This also means divers can enjoy their whaleshark experience to the maximum.

So a few rule or actually a bit of common sense really.

  • Do not touch the animal
  • Do not chase the animal
  • Stay a minimum of 4m away from the head and 6m away from the tail
  • Do not use flash photography
  • No Feeding

Unfortunately these fish are listed on the vulnerable species due to their small population size. The number of whale sharks has more than halved over the last 75 years, with legal and illegal fishing causing entanglement problems.

Whalesharks still get caught up in lines and nets as well as collide with boats and this is responsible for many premature deaths. Unfortunately, despite being on the endangered list they are still being hunted in certain areas of the world, with their fins being prized ingredients for shark fin soup.

Like human fingerprints, whale sharks have a unique pattern of spots that allow individual sharks to be identified. By taking photos and sharing them with ‘The Wildbook for Whalsharks photo-identification library’ (who’s website is https://www.whaleshark.org/) you can help marine biologists to learn more about these amazing creatures.

The library is a visual database of Whaleshark encounters and of individually catalogued Whalesharks. It uses photographs of skin patterns behind the gills and of any scars to distinguish between individual fish.

Author: Nina Horne (PADI MSDT #355693)

Crystal Dive Koh Tao

7/1 Moo 2
Tambon Ko Tao
Koh Tao
Surat Thani

E-mail: [email protected]

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