The Waikaretāheke River is a river of the Hawke's Bay region of New Zealand's North Island. It serves as the outflow of Lake Waikaremoana, flowing southeast from the lake's southeastern shore to reach the Waiau River northwest of Wairoa. State Highway 38 follows the river's course for much of its length.
Over 2000 years ago, a landslide blocked the Waikaretāheke River, which flooded river valleys. These valleys are now the arms of the Waikaretāheke.
On May 15, 2022, an emergency beacon was activated due to an incident involving a kayaker on the Waikaretāheke River. Emergency officials arrived too late to the scene, and the kayaker's deceased body was recovered from the river. 