Tonlé Sap

Tonlé Sap is Cambodia’s largest freshwater lake and a central part of the country’s inland water system, linked to the Mekong by the Tonlé Sap River. It is notable for its dramatic seasonal change in size and its importance to Cambodian fisheries and livelihoods.

The lake supports extensive floating villages and stilt-house communities where schools, markets, and homes move with the water; some villages are accessible by boat from Siem Reap. The flooded forests, river channels, and shoreline are the basis for boat tours that observe fishing activities, waterbirds, and local village life.

Local peoples have depended on the lake and its seasonal flood pulse for centuries for rice farming and fishing. The area was recognized for its global ecological value with designation as a UNESCO biosphere reserve in 1997.

Tonlé Sap lies in central Cambodia, with its northern shore adjacent to Siem Reap and its southern connection to the Mekong near Phnom Penh via the Tonlé Sap River. The lake and its floodplain dominate the lowland between Siem Reap and Phnom Penh.

• Seasonal size change: The lake expands dramatically between seasons, typically from roughly 2,500 km² in the dry season to more than 10,000 km² at peak flood, altering transport and wildlife habitats.
• UNESCO biosphere reserve: Designated a UNESCO biosphere reserve in 1997 for its ecological importance and role as Southeast Asia's most productive inland fishery.

What to See #

• Floating villages (e.g. Kampong Phluk, Chong Khneas): A number of permanent and seasonal floating villages on the lake and its channels, notable ones include communities near Siem Reap that rely on stilt houses and boats for transport and trade.
• Tonlé Sap River: The Tonlé Sap River channel that reverses flow seasonally, connecting the lake to the Mekong and driving the annual flood pulse that enlarges the lake in the rainy season.