Cambodia's largest island, about 25km south of Krong Koh Kong, towers over seas so crystal clear you can make out individual grains of sand in a couple of metres of water. Its seven pristine beaches, all of them along the western coast, get so few visitors that sand crabs scamper obliviously up and down the beach and the shoreline is dotted with colourful shells of the sort you usually see only in souvenir shops.

There's a police post near the 20km-long island's northern end, above the second beach you come to, so skippers may be reluctant to stop nearby - or even stick around the area too long. It's forbidden to explore the thickly forested interior. The island is not part of any national park or wildlife sanctuary and thus has few protections against rampant development.

Several of the beaches - lined with coconut palms and lush vegetation, just as you'd expect in a tropical paradise - are at the mouths of little streams. At the sixth beach from the north, a narrow channel leads to a genuine Gilligan's Island-style lagoon.

On Koh Kong Island's eastern side, half-a-dozen forested hills - the highest towers 407m above the sea - drop steeply to the mangrove-lined coast. The fishing village of Alatan, the island's only settlement (for now), is on the southeast coast facing the northwest corner of Botum Sakor National Park.