The Pyke River flows generally southward through the southwest corner of New Zealand's South Island, beginning at the confluence of Sealy Stream and Trinity Creek in Mount Aspiring National Park before passing through Fiordland National Park after meeting the Olivine River. It drains into Lake Wilmot, then Lake Alabaster, and ultimately joins the Hollyford River as a tributary. Its Māori name is Kaoreore.

The river is most commonly paddled as part of the Hollyford-Pyke Loop, a 5–6 day packrafting circuit that begins and ends at the Hollyford Road End near Gunn Camp. The Pyke section is typically paddled upstream to downstream, from the Big Bay coast crossing at Pyke Crossing through to Lake Alabaster and on to the Hollyford confluence, rated Class I with some Class II characteristics. The water is notably crystal clear in the upper reaches, with visibility to the riverbed giving a distinctive sensation of floating over rocks. Below Lake Wilmot, the flow slows and the water becomes more turbid. The river passes through dense beech forest and supports native eels and a variety of bird species including kākā, kea, mohua, and New Zealand falcon.

A significant practical consideration is didymo (Didymosphenia geminata): the Hollyford River, Lake McKerrow, and the southern end of Lake Alabaster are affected, while the Pyke River is currently didymo-free. The Department of Conservation recommends paddling the Hollyford first and the Pyke second, cleaning vessels thoroughly between the two using MPI guidelines, to avoid spreading didymo into the Pyke system.

Log hazards and strainers are present, particularly near the confluence with the Hollyford. Flooding is common throughout the area and can make travel impossible for days; paddlers should plan for delays and carry extra food. The Fiordland region receives approximately seven meters of rainfall annually, so wet weather should be expected at any time of year. Weather windows matter considerably for this trip, as the experience is oriented around views rather than whitewater.

Hut accommodation is available along the route, including Olivine Hut (recently rebuilt in 2025), Lake Alabaster Hut, and others on the Hollyford Track. A well-maintained track follows the river for approximately 1.2 km from the road end to the main channel, and a two-hour hike along the Hollyford Track returns paddlers to the road end at the conclusion of the loop.