A lone paddleboarder had a rare, once in a lifetime close encounter with a blue whale while paddling in Dana Point, California.

Endurance athlete Bill Clements was paddleboarding on August 24, looking for wildlife, when he spotted what he believed to be a boat's wake, before soon realising it was something much more special.

As he was staring over, he spotted a dorsal fin pierce the ocean surface and a blue whale five times longer than his 14ft paddle board breached the surface just metres away from him. 

Excited Bill started filming the mammal and caught his reaction on camera as the curious whale made several passes close to him.

At one point, the blue whale even rolled over at one point to look at him, with an overjoyed Bill exclaiming ‘It's looking at me! It's looking at me! Oh my Lord.’ 

Bill said: “I paddle for three to four hours at a time in search of dolphins and other ocean life, but this experience trumped anything I’d ever seen before in the open ocean. 

“I saw what I thought was a boat wake, but there were no boats in the vicinity, so I stared at the wake when suddenly the dorsal fin pierced the surface and a blue whale came up to breathe.

“It was heart stopping to be so close to something that big, it looked like a glowing blue submarine as it swam by me under the surface.

"I was so in awe of its presence I couldn't help but get a little choked up.”

ENDS