A Ningaloo Reef pilot has captured one of the rarest sights off the Exmouth coast, photographing two whale sharks in an intimate moment near the surface of the ocean.

In what is believed to be a world first, whale sharks were spotted mating in waters off Ningaloo Reef off the Exmouth coast. Credit:Ningaloo Aviation/Tiffany Klein

In what is believed to be one of the first times the world's largest living fish have been observed mating, Ningaloo Aviation owner Tiffany Klein photographed the sharks from above as she tracked them for swimming tours below on Monday.

Ms Klein said she followed the male shark for about two hours, spotting it for swimmers, before it was joined by a female.

"The male shark swam over to the female shark and instantly turned upside down, which is a very unusual behaviour," she said.