El Triunfo Lake is a lake in the Beni Department, Bolivia.

The El Triunfo lagoon is a Bolivian Amazon freshwater lagoon located in the east part of the Beni department, near the Guaporé River and 4 kilometers south of the border with Brazil. The lagoon dimensions are 5.8 kilometers in length by 5.1 kilometers in width, resulting in a surface area of 19.3 km (7.5 sq mi). Its coastal perimeter is 17 kilometers.

It is characterized by having a round shape as well as being surrounded by a thick jungle.