The Waianakarua River is a river in North Otago, New Zealand, flowing into the Pacific Ocean. It is crossed by State Highway 1 at the settlement of Waianakarua, south of Herbert. The river's estuary and associated swamp are a regionally significant wetland located approximately 3 km northeast of the intersection of Woodburn Road and Waianakarua Road. The estuary area is managed, and contact information for the Otago Yacht Club and the Dunedin City Council is provided for inquiries regarding this section. For paddlers, the river offers access points and facilities. The surrounding landscape includes access to hunting areas via Mount Misery Road off State Highway 1 north of Hampden, where a road suitable for all vehicles leads to a car park. The river's character is defined by its coastal plain flow into the ocean, with an ecologically significant estuary swamp at its mouth.