The Catlins River flows southeastward through The Catlins, an area of the southern South Island of New Zealand. Its total length is 42 kilometres (26 mi), and it flows into the Pacific Ocean at Pounawea, 28 kilometres (17 mi) south of Balclutha. Its upper estuary is called Catlins Lake, and its lower estuary is shared with the Owaka River.
The river's source is west of Mount Rosebery, 15 kilometres (9 mi) southwest of Clinton.
Coordinates: 46°29′S 169°43′E / 46.483°S 169.717°E