This is the heartwarming moment a kind fisherman freed a leatherback sea turtle snagged on a ghost net in Thailand.

Kanchit Padtan was hunting fish off Koh Pling island in Phang Nga province when he found the 200kg marine creature flailing near the surface with the net wrapped around its body on December 11.

Footage shows Kanchit and his friend cutting the yellow net tangled around the turtle's neck and flippers as the animal paddled next to his boat.

After several minutes, the leatherback turtle was released and was seen swimming away into the open waters.

The Department of Marine and Coastal Resources applauded Kanchit's good deed and said the turtle may have died without his help.

Leatherback turtles are the largest species of sea turtles, known for their distinctive leathery shell and lack of a bony carapace.

They are listed as vulnerable on the IUCN Red List, as bycatch, pollution, and habitat encroachment threaten their populations.