The Karamea River flows from the Allen Ranges through Kahurangi National Park to the Tasman Sea at the town of Karamea on the West Coast of New Zealand's South Island. It is a long river by New Zealand standards, draining a substantial catchment that historically provided a travel corridor for both Māori and early European explorers. The river passes through remote wilderness and pristine national park forest before reaching the coast.

The river can be divided into several distinct sections with varying character and difficulty. The upper reaches, accessed via the Wangapeka Track, offer a multi-day packrafting or kayaking experience typically rated as beginner-to-intermediate, with pool-drop whitewater and scenic gorges. A common put-in is Trevor Carter Hut, reached after approximately 30 kilometres of hiking. The upper sections include areas of lower-volume, twisty boulder gardens, followed by a mix of rapids, lakes, and portages through the Roaring Lion and Ferris Creek sections. The Karamea Gorge is the most serious section, containing rapids rated New Zealand Class IV, and demands significant whitewater experience. Below the gorge, the river eases considerably and can be floated with less technical effort to the road bridge takeout. The full Wangapeka–Karamea loop is considered an advanced trip of five to seven days, with Department of Conservation huts available most nights.

For flow guidance, a gauge reading of around 0.9–1.1 metres is suggested for a first packrafting trip on the upper river. The West Coast receives high rainfall, so paddlers should budget extra days to wait out significant rain events, as flows can rise and drop quickly.

The lower reaches near the river mouth offer a very different experience, rated around Grade 2, and are suitable for casual kayaking. The area around Karamea town also provides access to several lagoons for flat-water paddling. The river mouth and estuary are noted for trout and kahawai fishing.

The upper river is best accessed via the Wangapeka Track from the West Coast side. The fishing season runs October to May, which broadly aligns with the more favourable paddling season, though the river can be run year-round with appropriate caution regarding weather and water levels.