The Aorere River is a 43-kilometre river draining the Wakamarama and Haupiri ranges in the Kahurangi National Park region of Golden Bay, west of Nelson. It flows north to Golden Bay at Collingwood, which is roughly five minutes from the river's lower reaches and about two hours from Nelson. The river runs over a bed of round granite stone and large outcrops of solid rock, and remains clear at low flows, becoming turbid after heavy rain.

The character of the river changes significantly along its length. The lower reaches near Collingwood are deep and slow moving, becoming tidal in the vicinity of the town itself. Further upstream, the river transitions to faster flows with deep pools, particularly above the confluence with the Brown River at the start of the Heaphy Track, where the gradient and depth increase considerably. Access to the upper reaches requires walking along a defined track, as the road ends at the Heaphy Track start.

Several road access points exist along the middle and lower river, including Rockville Bridge on the Collingwood-Bainham Road, Salisbury Bridge off Aorere Valley Road, and various points along McKay Pass Road. These provide options for put-ins and take-outs along the more accessible sections.

Motorized vessel speed limits apply on the Aorere and are seasonally adjusted. From 1 September to 30 November, the speed limit is uplifted only between the Brown River confluence and Rockville. From 1 December to 31 August, the speed limit is uplifted from the Brown River confluence all the way to the sea. Paddlers should be aware that during the December to August period in particular, motorized craft may be operating at higher speeds on a longer stretch of river. General maritime rules apply to all small craft including kayaks, and paddlers are encouraged to display brightly colored equipment to aid visibility.