Tonle Sap Lake

The Tonle Sap remains relatively small for most of the year, measuring about a meter in depth and covering around 2,700 square kilometers.

However, the river that connects to the lake starts to swell during the monsoon season as water that flows from the Mekong river reverses, helping to expand the Tonle Sap up to 16,000 square kilometers with a depth up to 9 metres deep.



Surrounding fields become flooded with the floodplains acting as the core breeding ground for the Tonle Sap’s plentiful supply of fish.

The seasonal flow from lake and river are responsible for creating more than 75% of Cambodia’s fresh water fish catch and are estimated to directly support more than 3 million people.

Tonle Sap Statistics

  • Surface area of 2,700 km² (normal)
  • 16,000 km² (monsoon)
  • Designated as a UNESCO biosphere in 1997
  • Supports more than 3 million people
  • Responsible for with 75% of Cambodia’s annual inland fish catch
  • Provides around 50% of the flow to the Mekong Delta in Vietnam