Anchored to alluvial islands – some no larger than a house – this 260-sq-km sanctuary’s magnificent mangroves protect the coast from erosion, offer vital breeding and feeding grounds for fish, shrimp and shellfish, and are home to myriad birds. To get a feel for the delicate mangrove ecosystem, head to the park entrance, 5.5km east of Koh Kong, where a mangrove walk wends its way above the briny waters to a 15m observation tower. A moto/tuk tuk ride costs US$5/8 return.
Travellers with little ones in tow should keep a vigilant eye on children as the walkway is not well maintained. If you're lucky, you'll come across cavorting monkeys with a fondness for fizzy drinks. Also here are a restaurant and the Mangrove Sanctuary Resort.
You can hire a motorboat to take you through the sanctuary; wooden boats are available for hire from the dock at the sanctuary entrance. Short tours cost US$25 for up to eight people. Half-day trips (US$60) head deeper into the sanctuary's interior, while full-day tours (US$90) include Koh Kong Island (high season only). Fishing is possible. Tour companies in town arrange cheaper half-day and full-day group tours of the sanctuary, with departures from the city boat dock.
On a boat tour you’ll have a chance to visit fishing hamlets where residents use spindly traps to catch fish, which they keep alive till market time in partly submerged nets attached to floating wooden frames. Further out, on some of the more remote mangrove islands, you pass isolated little beaches where you can land and lounge alongside ambling hermit crabs.
Much of Peam Krasaop is on the prestigious Ramsar List of Wetlands of International Importance (www.ramsar.org). The area, which is part of the Koh Kong Conservation Corridor, is all the more valuable from an ecological standpoint because similar forests in Thailand have been trashed by short-sighted development.
Unfortunately Peam Krasaop's habitats and fisheries are threatened by large-scale sand-dredging operations controlled by Cambodian tycoon Ly Yong Phat. Kalyanee Mam's 'short film A Lost World brought attention to the issue, which saw more than 72 million tons of sand exported to Singapore from 2007 to 2017, according to the UN. In 2017 the Cambodian government halted sand exports to Singapore. But the equipment remains ominously in place and residents fear that large-scale dredging will resume to serve domestic needs – if it hasn't already.