The San Juan River (Spanish: Río San Juan) is a Colombian river that flows into the Pacific Ocean through the Chocó Department.

The river drains into a large delta that covers nearly 300 square kilometres (120 sq mi).

The river begins on Cerro Caramanta in the West Andes.

The delta is due north of Bahía Málaga and Buenaventura.

[1] Monthly average flow of San Juan River ( m³/second) measured at Penitas stationData from 25 years[2] A species of snake, Dipsas sanctijoannis, is named after the San Juan River of Colombia, and is native to the watershed.