The Haast River is a glacially fed waterway in the World Heritage region on the West Coast of New Zealand's South Island, running nearly 100 kilometres through the Haast Valley. Fed by snowmelt from the Southern Alps, the water is a striking emerald green and extremely cold. The river cuts through west coast rainforest before broadening into a braided, fast-moving channel as it approaches the coast. As a braided river, it changes course and direction frequently, a characteristic that shapes the paddling experience throughout.

The upper reaches begin as serious whitewater at Haast Pass, but the lower half of the river, from the grassy flats beyond Pleasant Flat, is graded Class I and suitable for beginners. Two practical put-in options exist for this lower section: Roaring Billy Falls, approximately 30 kilometres from the Haast Bridge, or Pleasant Flat Campsite, roughly 50 kilometres from the bridge. The standard take-out is on the north slope just before the Haast Bridge itself, a point used by both commercial and private boaters. In normal conditions, the run from Roaring Billy Falls to the bridge takes around four hours.

While the lower section is generally mild, there are a few Class II rapids along the way. These can be portaged at easy exit points for those who prefer to avoid them. One section requiring particular attention is just below where a lake rejoins the river — this stretch has been noted for fast-moving water with strainers and should be treated as a portage. Paddlers should remain alert throughout, as the fast current demands consistent attention even where the gradient is low.

The Haast Bridge, at 737 metres, is the longest single-lane bridge in New Zealand and serves as a useful landmark for the take-out. The village of Haast, located near the river mouth, may be able to arrange shuttle services for paddlers without a second vehicle. Hitchhiking from the north end of the Haast Bridge is another option commonly used to return to upstream put-ins. Pleasant Flat, the starting point for the beginner-friendly section, is located 161 kilometres from Queenstown via a winding road through mountain passes and rainforest.