A massive leatherback sea turtle has laid its eggs on a beach in Phuket, Thailand, for the first time in 20 years.

The enormous 300kg marine creature was spotted shuffling across the Karon Beach by Centara Grand Resort Phuket hotel staff on July 25 evening.

They reported the sighting to Suthep Jualaong, director of the Phuket Marine Biological Center, who coordinated with local officials to cordone off the area for inspection.

A team arrived at around 11:07 PM and put up an enclosure to allow the turtle to lay its eggs undisturbed.

Suthep said that the turtle had emerged from the sea to find a suitable spot to deposit its eggs, as shown by the trail it left on the sand.

He said the soon-to-be mum had dug up three pits, but chose just one to use. The pit was located away from the water, he said.

Officials today have established a protective perimeter around the nest to shield it from the waves, with plans to later relocate the eggs for counting and hatching.

Suthep said it was the first time in 20 years that a leatherback sea turtle had laid eggs in Karon Beach.