Whale Shark

The whale shark is the world’s largest fish — and one of the most thrilling encounters in all of diving. Despite their enormous size (up to 12 metres, though 6–8m is more typical in Thai waters), whale sharks are gentle filter feeders, swimming slowly with their cavernous mouths open to strain plankton from the water. They are entirely uninterested in divers and will swim placidly past, occasionally so close you could reach out and touch them (please don’t).

In Thailand

Thailand is one of the world’s most reliable countries for whale shark encounters. The Gulf of Thailand and Andaman Sea both host seasonal concentrations, with Chumphon Pinnacle near Koh Tao being the most famous Gulf of Thailand site and Richelieu Rock in the Surin Islands being the premier Andaman site.

When to See Them

In the Gulf of Thailand, peak season is March–May and again September–October. In the Andaman, February–May is the prime period, with Richelieu Rock producing almost daily sightings during April.

The Experience

No amount of preparation describes the experience of a whale shark appearing from the blue. The sheer scale — filling your entire field of vision, moving with a lazy tail sweep that somehow covers enormous ground — is unlike anything else in diving. Time seems to stop. The encounter typically lasts 5–20 minutes as the shark passes or circles the dive site.

Conservation Note

Whale sharks are classified as Endangered on the IUCN Red List. Always maintain a respectful distance, never touch or ride them, and don’t use flash photography (which can startle them). Many Thai operators follow PADI’s responsible whale shark encounter guidelines.