Obama pictured snorkelling in the Pacific Ocean

Outgoing US President Barack Obama has been pictured swimming in the Pacific Ocean in an area he protected as a Marine National Monument.

President Barack Obama looks out over Turtle Beach as he tours Midway Atoll in the Papahanaumokuakea Marine National Monument, northwestern Hawaiian Islands. Source: AAP

A photographer has captured the moment outgoing US President Barack Obama went for a swim over a coral reef in the Pacific Ocean on his Hawaii trip.

The remote reef, halfway between California and China, is part of the Papahānaumokuākea Marine National Monument, which President Obama quadrupled in size in August, 2016 in order to protect the region for future generations.

National Geographic photographer Brian Skerry captured the moment the President went for a snorkel over the reef near Midway Atoll's Sand Island.

The magazine reported Mr Obama, who grew up in Hawaii, appeared relaxed away from the hustle and bustle of Washington politics and later recalled his experience at an oceans conference.

"I saw it," he said. “It was right there - evidence of the incredible power of nature to rebuild itself if we’re not consistently trying to tear it down.”