The Wairoa River, located in the Bay of Plenty region near Tauranga on New Zealand's North Island, is the largest watershed draining into Tauranga Harbour. Its name translates to "long water," and it is formed by the merging of the Mangapapa and Mangakarengorengo rivers just above McLaren Falls. The river drains numerous smaller streams, all of which can offer additional paddling when levels are sufficient.

The whitewater section is a class 4–5 run featuring small waterfalls and steep boulder garden rapids, with the most significant rapids concentrated in the first half of the run. Named features include Mother's Nightmare, a technical grade 4 rock garden followed by a 2-metre drop; the Rollercoaster, which includes the Devils Cauldron and Bottom Drop; and a 3-metre waterfall drop. The Rollercoaster can be approached via a sneak route from the right or down the central line into the Cauldron, and lines can be scouted from the right using fixed ropes to access viewing ledges. A serious hazard exists approximately 30 metres below the Rollercoaster: a nasty undercut wall sits directly in the runout zone and must be avoided. A safety rope is available hanging from the cliffs above. The gradient eases considerably in the lower section, which includes class II–III rapids, a rock splat wall, and a 2-metre ledge drop.

The river is dam-controlled, and paddling is only possible on scheduled release days. During summer months, releases occur every Sunday; they are less frequent throughout the rest of the year. Because the river is only runnable on release days, it is open for a limited number of days annually. Paddlers should check release schedules in advance.

Put-in options exist at the top of the run or at a midway point below the Rollercoaster, accessible via private property through Browns Farm on a well-maintained track. A fee of $5 per kayaker applies for the midway put-in, payable via an honesty box. Take-out options include the Kaimai Canoe Club clubrooms or continuing approximately one kilometre further to the Ruahihi Power Station take-out. The lower section through Browns Farm carries a separate $2 per person per day access fee.

The upper reaches near Omanawa offer a contrasting flat-water experience suitable for beginners, with no prior kayaking experience required for that section.