Koh Rong is the larger of the two sisters and wears its size well. Most of the island is still forest, a green interior of hornbills and butterflies that the building along the beaches has barely touched. You arrive at Koh Touch, on the eastern side, where the boats land and the island is at its loudest, then spend the rest of your stay working out how far from that you want to get.
Koh Touch, the loud and friendly east
Koh Touch is a short strip of guesthouses, dive shops and bars, backed by a beach that fills with day-trippers and empties again by late afternoon. It has a cheerful, slightly sunburnt energy, and it is the easiest place on the island to arrange a boat, a dive, or a plate of barbecued fish. Stay a night to enjoy it, then move.
The long white west
Walk or boat around to the western shore and the island changes character completely. Long Set Beach, which many people still call 4K for its roughly four kilometres of sand, runs in a near-empty white arc that the day boats rarely reach. Further south, Sok San village sits at the quiet end of another long beach. This is the Koh Rong people picture when they imagine a Cambodian island: pale sand, warm shallow water, and almost nobody on it.
Into the trees
The interior is the island's secret. Rough trails cross from one coast to the other through genuine jungle, past the odd stream and waterfall, loud with insects and birdsong. Guides from the villages will take you, and it is worth the sweat, if only to understand that the beaches are a thin bright edge on something far wilder.
Getting there and around
Fast boats run from Sihanoukville several times a day and take roughly three-quarters of an hour. Once you land, the island moves on boats and your own two feet more than on roads, so pack light and keep it waterproof. Give Koh Rong enough days to reach the far side, where it keeps its best and quietest beaches for the travellers who bother to go looking.