Tonlé Sap Lake – Cambodia’s Great Lake
Tonlé Sap Lake, located in the heart of Cambodia, is the largest freshwater lake in Southeast Asia and one of the most productive inland fisheries in the world. It is often called the “Great Lake” because of its immense ecological and cultural importance.
A Unique Natural Phenomenon
What makes Tonlé Sap truly remarkable is its connection to the Mekong River. Each year, during the rainy season (June to October), heavy rainfall and melting snow from the Himalayas cause the Mekong River to rise. This forces water to flow backward into the Tonlé Sap River, dramatically expanding the lake’s size from about 2,500 square kilometers to over 12,000 square kilometers.
When the dry season returns, the flow reverses, and the lake’s waters drain back into the Mekong, shrinking its size once again. This natural flood pulse creates one of the most fertile and biodiverse regions in Southeast Asia.
Ecological Importance
The floodplain surrounding Tonlé Sap is rich in nutrients, supporting vast numbers of fish, birds, and other wildlife. The lake is home to over 300 species of fish, 20 species of snakes, 10 species of turtles, and dozens of water birds, including rare and endangered species such as the spot-billed pelican and the greater adjutant stork.
In 1997, UNESCO designated the Tonlé Sap Biosphere Reserve to help protect this vital ecosystem.
Human Life on the Lake
Over one million people depend on Tonlé Sap for their livelihoods. Many live in floating villages or stilted houses that rise and fall with the lake’s water level. These communities rely on fishing, small-scale farming, and tourism. Floating schools, markets, and even pagodas can be found across the lake, showing how deeply human life is connected to this unique environment.
Visiting Tonlé Sap
The lake is easily accessible from Siem Reap, and visitors can explore villages such as Kampong Phluk, Kampong Khleang, and Chong Khneas. Boat tours offer insights into local life and the natural beauty of the area, while birdwatching trips are especially popular in the Prek Toal Bird Sanctuary. We at Tara Riverboat tours explore all these villages and much more.