Mtamvuna River is a river that forms the border between KwaZulu-Natal and the Eastern Cape Provinces in South Africa. The river has a wide mouth and flows into the Indian Ocean just south of Port Edward. The Mtamvuna river is approximately 162 km long with a catchment area of 1,553 km². The name means "the reaper of mouthfuls" because of the damage the river does to crops during floods.