There is not much island here, but there is a great deal of coastline for its size - six kilometres of shore wrapped around a landmass never more than 1.7 kilometres across and in places as narrow as seven hundred metres. That ratio is the whole appeal. Whichever side you land on, you can walk to the other in under half an hour, and the two shores catch entirely different light. Administratively it belongs to Prey Nob District in Preah Sihanouk Province, which is a formal way of describing an island with no permanent village. Beachcombers rate it highly for shells, the reward for that coarse sand: fine sand grinds shells to nothing, while a coarse beach delivers them more or less intact.

For most of its documented existence, Koh Russei was not a destination at all. It served as a small outpost of the Cambodian Navy and nothing else, which is less unusual on this coast than it sounds - Cambodia's offshore islands have long carried small garrisons, and the mainland shore just to the east holds Ream Naval Base among the mangroves. One of the two traditional ways to reach Bamboo Island is still from the beach near Ream National Park, about twenty kilometres east of Sihanoukville, which means the boat ride to the most relaxed place on the coast begins next door to its most contested one. The other approach was pure improvisation: ask the owner of the Sunset Cafe on Occidental Beach the night before, and a private boat cost five dollars.

What grew here once Sihanoukville's tourist numbers climbed was about as unpolished as coastal tourism gets. Two clusters of huts faced each other from opposite sides of the island, roughly ten to a cluster, each with its own bar and restaurant, at ten to twenty US dollars a night. Bookings went through the Koh Ru office or Coasters Guesthouse back on the mainland. Nobody had put a bank or an ATM on the island, so you brought cash or you went without. Water and electricity ran for part of the day rather than all of it, showers meant a bucket, and toilets were shared. Prices sat around fifty per cent above the Sihanoukville average, which travellers accepted as the cost of being on an island instead of near one. It was, by every account written at the time, a lovely and slightly ramshackle way to spend a few days.

Sihanoukville was built in 1955 for a strictly practical reason: newly independent Cambodia wanted a deep-water port of its own rather than depending on Vietnamese control of the Mekong Delta. The city was formally founded on 22 November 1957 and named for King Norodom Sihanouk, though its older name, Kampong Saom, is far more evocative - Port of the Moon. It stayed small. As late as 2019 the city held roughly 73,000 residents, and by then something extraordinary had happened around them: close to 80,000 mainland Chinese workers and investors had arrived, about ninety per cent of the foreign population, with more than a hundred casinos planned. The online gambling ban of 2019 and the pandemic that followed gutted the business, and by 2023 parts of the city had become notorious for compounds where trafficked people were forced to run online fraud. Half-built towers still stand along the shore. All of this happened within sight of Bamboo Island.

Koh Russei was never going to sit out that boom. The investment company Citystar drew up plans for a low-density villa community and a luxury hotel on the island, to be built against EarthCheck environmental benchmarks and finished by 2016. Nearby Koh Puos - Snake Island - had already gone the same way. The scheme arrived a couple of years behind that target: the resort opened on 1 November 2018 as Alila Villas Koh Russey, a 50-pavilion, 13-villa property built to EarthCheck's top sustainability certification, and now trades under the Koh Russey Resort name. The direction of travel on this coast has been consistent for two decades, and bamboo huts at ten dollars a night have rarely survived it anywhere. What is not negotiable is the beach itself. The shallows will keep running out absurdly far, the shells will keep washing up whole, and the sand will keep being too coarse for bare feet, whatever stands above the tideline today.