The Whau River is a tidal river in West Auckland that flows into the Waitematā Harbour. Its Māori name, Te Whau, derives from the whau plant (Entelea arborescens), and the river sits within the broader area historically known as Te Wao nui o Tiriwa, the great forest of Tiriwa. The river has long been associated with water-based activity; in the 20th century it hosted regattas for rowing and power boats, and boating and boat building remain significant uses of the waterway today.

For paddlers, the river is navigable by kayak and waka ama, with organised kayak events including clean-up paddles regularly held on the water. As a tidal river, conditions are influenced by tidal cycles, and king tides are a notable consideration when planning a trip. The public boat ramp at Archibald Park, which has an associated car park, is the primary public launch point in the area. Te Atatu Boat Club also provides wharves and launching facilities, though these are private. A boat ramp at the end of Bridge Avenue exists but has been noted as largely unusable due to sedimentation. Informal access points occur sporadically along the banks, including near Roberts Road, under the railway bridge, and via a steep path to Karaka Park at Green Bay, though these are uncontrolled.

The river corridor is the subject of active ecological restoration efforts led by community organisations including the Whau River Catchment Trust and Friends of the Whau. The Te Whau Pathway project is developing a walking and cycling route along the river, with sections between Roberts Field and New Lynn still under development. The waterway passes through the suburbs of Glendene, New Lynn, and Te Atatu, and connects to the broader Waitematā Harbour, placing it on the western side of Auckland's harbour system.