The Clutha River / Mata-Au is the highest-volume river in New Zealand and the longest in the South Island, flowing south-southeast approximately 338 kilometres. Its catchment covers 21,960 square kilometres and it discharges a mean flow of 614 cubic metres per second. The river originates at the outlet of Lake Wānaka and ultimately reaches the sea, making a full source-to-sea journey feasible in approximately five to six days by packraft or kayak.

The upper section, from the Lake Wānaka outlet to Albert Town, is the most accessible stretch for paddlers. Boat ramps are located at the Outlet, Albert Town, and Bendigo. Much of the river is willow-lined, and dense riparian vegetation can limit access to the water's edge in places, requiring some walking to reach put-in points. Downstream from Albert Town, access points are marked from State Highways with blue angler access markers, though some tracks require a 4WD vehicle. The Queenstown Lakes District Council enforces navigational safety bylaws between the Outlet and Albert Town, so paddlers should review the QLDC Navigational Safety Bylaw 2018 before launching in that section.

The flow on the upper river is influenced by the hydro dam at Clyde, which causes fluctuations between approximately 200 and 600 cumecs, though by Alexandra the flow tends to be relatively constant. The river carries a strong current throughout, and even without active paddling, speeds of around 8 km/h have been recorded on the Alexandra to Roxborough Gorge section. The character of the river is predominantly Grade 2, with the full journey described as manageable for paddlers competent in a river environment and comfortable on moving flatwater. A sea kayak is considered suitable for confident paddlers.

The river passes through historically significant landscapes, with strong associations with early European and Chinese settlement, gold mining, and pastoral development. Physical remnants of sluicing and dredging remain visible along the banks. The upper river is also a popular destination for jet boating and fly fishing, so paddlers should expect other river users, particularly on the upper reaches. The lower river near the mouth passes through more remote terrain, including areas of abandoned farmland near the coast. Camping is available at Albert Town campground, with freedom camping for self-contained vehicles permitted at accessible spots along the river outside prohibited zones.