It forms an anticlockwise loop through the southern scenic regions of the Mackenzie Basin and Central Otago, starting and terminating in junctions with State Highway 1.

For most of its length SH8 is a two-lane single carriageway, with at-grade intersections and property accesses directly off the road, both in rural and urban areas.

The highway leaves SH1 at Washdyke, an industrial suburb of Timaru, travelling initially northwest through Pleasant Point then continuing to the town of Fairlie.

From here the route tends westward and rapidly increases in altitude, passing the southern end of the two great Mackenzie Basin lakes of Tekapo and Pukaki.

From here, the highway continues past Waitahuna and the twisting Manuka Gorge, reaching the plain of the Tokomairaro River at Clarksville, three kilometres south of Milton.