Jirasak Putthawan, manager of a diving shop on the main Phi Phi island in Tambon Ao Nang of Muang district, said he had led his clients to dive off Koh Bida Nok on Sunday when they encountered the estimated six-metre-long whale shark.
Jirasak posted a video clip on his Facebook wall on Sunday, showing the whale shark moving towards the divers and swimming around close to them for about a minute.
The team was diving to see the beauty of corals at the spot and were thrilled to get up close unexpectedly to a whale shark.
Jirasak believes the undersea environment has rehabilitated itself during the Covid-19 pandemic when not many tourists visited the Phi Phi islands, allowing a lot of fish species to return to the area.