The Greenstone River in Otago is a prized medium-sized freestone river renowned for its excellent rainbow trout fishing. Flowing through spectacular backcountry scenery, this river serves as a major spawning tributary for Lake Wakatipu, offering anglers approximately 28 kilometers of fishable water. The river's clear, cold waters and varied structure provide a classic New Zealand fly-fishing experience, with a focus on wild, self-sustaining trout populations. Access is managed to preserve the quality of the fishery, particularly in its upper reaches.