Tonlé Sap Lake Cruises

Tonle, which means “Large Fresh Water River” or simply “Great Lake,” is a combined lake and river system of major importance to Cambodia. The Tonle Sap is the largest freshwater lake in Southeast Asia and is an ecological treasure trove. The Tonle Sap is unusual for two reasons: its flow changes direction twice a year, and the portion that forms the lake expands and shrinks dramatically with the seasons.

From November to May, Cambodia’s dry season, the Tonle Sap drains into the Mekong River at Phnom Penh. However, when the year’s heavy rains begin in June, the Tonle Sap backs up to form an enormous lake, flooding nearby fields and forests and providing a breeding ground for local fish species. The Tonle Sap is one of the most productive inland fisheries in the world, supporting over three million people and providing over 75 percent of Cambodia’s annual inland fish catch and 60 percent of Cambodians’ protein intake. At the end of the rainy season, the flow reverses and the fish are carried down river. The reversal of the Tonle Sap River’s flow also acts as a safety valve to prevent flooding further downstream. During the dry season, the Tonle Sap Lake provides around 50% of the water flowing to the Mekong Delta in Vietnam.

The Tonle Sap Lake occupies a depression created due to the geological stress induced by the collision of the Indian subcontinent with Asia. The lake and its surrounding provinces, including Kampong Chhnang, Kampong Thom and Siem Reap, are part of the Tonle Sap Biosphere Reserve. The area is home to many ethnic Vietnamese and numerous Cham communities, living in floating villages around the lake.