- Nudibranch
- Jorunna funebrisScientific Name
- Least ConcernIUCN Threatened Status
Whale Shark
The whale shark is the largest fish species on Earth and one of the most sought-after marine life encounters around Koh Tao. Despite their immense size, whale sharks feed primarily on plankton and pose no threat to divers.
Endangered
Overview
The whale shark is the largest fish species in the world and one of the most exciting marine life encounters available to divers in the Gulf of Thailand. Despite growing to lengths exceeding 12 meters, whale sharks are gentle filter feeders that pose no danger to humans.
Whale sharks are occasional visitors to Koh Tao’s offshore dive sites, particularly Chumphon Pinnacle, Southwest Pinnacle, and Sail Rock. Sightings can never be guaranteed, which is part of what makes an encounter so memorable. Divers may go months without seeing one before experiencing multiple sightings within a short period.
These enormous fish feed primarily on plankton, fish eggs, and other tiny organisms suspended in the water column. Their broad mouths can filter thousands of liters of water every hour while they cruise slowly through nutrient-rich areas.
Each whale shark has a unique pattern of white spots and stripes, allowing researchers to identify individual animals in much the same way fingerprints are used to identify people. Conservation organizations around the world use photo-identification databases to track migration patterns and population movements.
For many divers, seeing a whale shark is a bucket-list experience. While Koh Tao cannot promise sightings, the island’s offshore pinnacles remain some of the best places in Thailand to encounter these magnificent animals.
Identification
The whale shark's most distinctive feature: pale yellow or white spots and stripes arranged in a unique grid pattern across a dark grey-to-brown body. No two individuals share the same pattern, making photo-ID possible from a single good flank shot.
Beth Siobhan
Unlike most sharks, the whale shark's mouth sits at the very front of a broad, flat head rather than underneath it. When feeding, the mouth opens wide and the animal swims slowly forward, filtering plankton through its gill rakers.
Beth Siobhan
Conservation Notes
Whale sharks are a protected species in Thailand. Maintain a minimum distance of 3 metres at all times and never position yourself directly above or below the animal. Do not touch, chase, or attempt to ride — even incidental contact causes stress. Switch off dive lights if one approaches at night. If one surfaces near the boat, cut the engine immediately.
Whale Shark Facts
Where to find them
Whale sharks are pelagic visitors rather than permanent residents — encounters can’t be guaranteed, but Koh Tao sits in one of Thailand’s most reliable corridors for sightings. Southwest Pinnacle and Chumphon Pinnacle are the most consistent locations, particularly during plankton bloom conditions when visibility may be reduced but the feeding is good. Sail Rock, further offshore, sees sightings year-round with the highest frequency between March and June. When one appears, it tends to arrive without warning from the blue — keep your head up and scan the water column, not just the reef.
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