Pokaiwhenua Stream is a tributary that flows into the southern end of Lake Karapiro in the Waikato region of New Zealand's North Island. The stream originates in the hills near the Mamaku Plateau, the same area that feeds the Putaruru Blue Spring, and carves a canyon through the landscape before meeting the lake. The lower section of the stream is accessible from Horahora Road near the mouth, with foot access available from the Aniwanawa Reserve on Horahora Road. Two additional road crossings exist further upstream: the Arapuni-Putaruru Road near a waterfall, and the Old Taupo Road a few kilometres above the waterfall.

The primary paddling experience involves launching from the Lake Karapiro area and paddling up into the canyon carved by the stream over hundreds of years. The canyon is characterised by dense native ferns and large trees whose canopy extends over the water, creating an enclosed, shaded environment. Birdsong is a consistent feature of the experience. The current in the stream means that the return journey downstream requires little to no paddling effort, while paddlers heading back across the lake may encounter wind depending on conditions.

Tours operate year-round, with daytime departures and twilight options available through local operators. The twilight tours take advantage of glowworm (titiwai) populations visible along the canyon walls after dark. Guided tours typically cover the southern edge of Lake Karapiro, passing over the site of the submerged Horahora Village and an old dam that once generated electricity for the Waihi goldfields, before entering the stream canyon.

Paddlers on the lake and stream are required to wear a PFD at all times and carry at least one form of waterproof communications, such as a mobile phone in a dry bag. Stand-up paddleboards used in surf conditions are exempt from the communications requirement provided the paddler is leashed to the board. The stream is also a designated fishing waterway open year-round under Auckland/Waikato regulations, so paddlers may encounter anglers, particularly in the lower reaches and around the stream mouth where larger fish are present.