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.
Legend says that any person failing to confess his sins before fording the river will be carried away by the water spirits. It is also supposed to be the home of mermaids, who have often been reported playing in the water on moonlit nights.