Diving with Whale sharks around Koh Tao


One of the perks of living on Koh Tao for 17 years is I’ve seen my fair share of Whalesharks, although I did have to wait a while for my first experience with these gentle giants of the oceans. Many of the fantastic experiences I’ve had diving with Whalesharks have blurred as the years have passed, but I still remember my first sighting as if it was yesterday.


Monsoon Madness

It was a dark and wet day, sometime in the middle of November 1999 and we were in the middle of the monsoon months. Back in those days Koh Tao was very quiet during the winter months, and I’d spent the morning servicing some of Crystal’s regulators.

The few dive boats operating that day had made the journey out to Chumphon Pinnacle and where heading back towards the island, sensibly looking for a suitable second dive site, sheltered from the elements, as the waves and wind had picked up significantly in the previous 30 minutes.

Shalaam Wan

My attention was drawn to a group of colleagues excitedly listening to the dive centre radio which was fixed on the 146.0 channel all Koh Tao’s boat captains used. One of the boat captains, talking quite excitedly kept repeating the words ‘Shalaam Wan tee kong Chumphon’ and I turned to one of our Thai staff at Crystal and asked what does ‘Shalom Wan’ mean?


Whaleshark! There is a Whaleshark at Chumphon Pinnacle right now!

Go, Go, Go….

Quickly the word spread and within a few minutes the suggestion was made – “shall we take the speedboat out and look for him?” Crystal was a much smaller operation in those days and the owner Khun Watcharin, himself a PADI Advanced Open water diver, rallied the boys to get the speedboat ready. Myself and a few of the Instructors ran off to pack our kit, grab some full tanks, a first aid kit, the emergency O2 and we where off.

It was a pretty hairy speedboat ride out to Chumphon that day. I remember passing one of the larger dive boats, heading in the opposite direction, and the look on the faces of the divers as they watched our small speedboat, bouncing around heading out towards the black was of disbelieve. The clouds had closed in, the rain was pretty heavy and you literally couldn’t see more than 20 metres ahead of you.

As soon as we pulled up to the dive site we all slipped straight in, which although no easy feat on a speedboat in bad weather, was significantly easier than if we had student divers with us. There were no boats on site so we had the place to ourselves.

Close Encounters At Gotham City

We had discussed and agreed on our dive plan on the journey out and we quickly descended under the swell in buddy teams. The change from the chaos of the surface conditions was soothing. I could see the top of the pinnacle. Considering the conditions on the surface, and the lack of sunlight (even though it was 10 o’clock in the morning) it was remarkably clear.

As Chumphon Pinnacle came into focus, void of divers, teaming with life, it had that ‘Gotham City’ look about it that many divers who have dived the site on an overcast day will attest to. Looking out, off the site and into the void there was just blue. An amazingly dark, but kind of clear almost royal blue. 

For a second I was in a trance, almost hypnotized probably due to straining my eyes looking out into the abyss in the hope of seeing the Whaleshark. Then the blue darkened and I snapped back into focus.

Slowly, emerging out of the blue was what looked like a dark shadow. Straining my eyes for a few seconds longer, and out of the dark shadow I could begin to make out white markings, and then the confirmation….it was the big spotted fish.

I remember the first thing that came into my mind – ‘Close encounters of the Whaleshark kind’

The ‘WOW’ Factor

‘Wow’ – what a feeling as it approached and came into full view.

Anyone that has experienced swimming with a Whaleshark will understand what an exciting, exhilarating and almost surreal experience it is. Being with a group of experienced divers, almost all working PADI Professionals, and with the dive site to ourselves I had the luxury of taking in my first Whaleshark encounter in all its amazing glory.

The Whaleshark was between 4 and 5 metres in length and although I’m sure he would have been the same fish the other dive centres dived with earlier he was extremely inquisitive and very friendly, as he swam around us, around the pinnacle and then back straight at us, literally head on.


All in all he stayed with us for over 15 minutes before swimming off into the same deep blue void he had appeared from. Thousands upon thousands of divers, who have dived Koh Tao have similar stories to mine. Many have been lucky enough to have spotted Whalesharks multiple times, as I have but I’m sure they will agree when I say it doesn’t get any less exciting.

The past 5-6 weeks we have been fortunate enough to see Whalesharks at Sail Rock during September and then a spate of sightings in the first week of this month – interestingly all three sightings where at dive sites east of the island; Hin WongLaem Thien and of all places Lighthouse – although the pinnacle somewhat out of the bay. And then yesterday we saw another Whaleshark, this time at White Rock.

A few facts about this big spotted fish….

A Shark, Not A Whale

It’s a shark, not a whale – whalesharks are fish and breath through their gills.

They are named Whaleshark because of their size, and the fact they are filter feeders, like whales. However, they have cartilage, instead of bone making them a true shark.

The Big Spotted Fish

Whaleshark’s display a distinctive pattern of white spots, on a dark grey background with a white underbelly. The pattern is unique to each individual – which makes life easier for scientists monitoring them.


They are the largest fish in the world. The largest confirmed individual measured 12.65 metres (41.50 ft) in length, weighing approximately 21.5 metric tons (47,000 lb). However, there have been unconfirmed reports of Whalesharks up to 20 metres long!

Almost Vegetarian

Whalesharks are Filter feeders. They eat minute plankton including krill, crab larvae and jellyfish. It also feeds on clouds of eggs during mass spawning of fish and corals.

A Whalesharks mouth can be as big as 1.5 m wide and contain as many as 3000 tiny teeth.

Will You Still Love Me, When I’m 64?

Little is known about a whalesharks lifespan but estimations suggest they live between 70 & 100 years.

Females give birth to live young that develop from eggs inside the mother prior to birth. As many as 300 are born, measuring 40-70cm in length.


Whalesharks are found throughout tropical and temperate waters. They are spotted in areas such as the Maldives, along the coastlines of Madagascar, Mozambique, Kenya, Pakistan, South Africa, Sri Lanka, India, Thailand, Indonesia and Malaysia plus Utila in Mexico and Puerto Rica. They are also seen in Australian waters off Queensland, northern Western Australia, and the Northern Territory.

The Human Threat – An Endangered Species

Whalesharks are consider vulnerable by the ICUN and a listed species by the Convention on Migratory Species (CMS) yet only 13, of the approximate 100 countries these beautiful creatures visit protect the species including the Philippines, Australia and India.

Unfortunately there are still areas where unregulated fishing and hunting for Whalesharks occurs. They are hunted for liver oil, cartilage and its fins which are used in Shark fin soup. There is also a market for Whaleshark meat in several countries.

Whaleshark Season

A common question we are asked is “What’s the best time to come to Koh Tao to see the whalesharks”.
Although March to June is often referred to as ‘Whale shark season’ on Koh Tao, and I have seen many during this time – including 3 on my birthday in April whilst teaching Open water training dives 3 & 4 with 4 student divers – these magnificent creatures are spotted year round.


October – December, in my opinion, always seems to be a good time to see Whalesharks. And you have the added bonus of a much quieter island. In 2012 we went through one of the most prolonged periods of regular sighting in October / November when there were multiple sightings at multiple dive sites simultaneously.

I remember one year, our dive boat returned from Chumphon Pinnacle after the morning dives on the 24th December – Christmas had certainly come early for those happy divers!

Author: Matt Bolton (PADI CD #463559)

Crystal Dive Koh Tao

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

E-mail: [email protected]

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