The South Island section of SH 1 starts in Picton, adjacent to the railway station. Leaving Picton, SH 1 rises steeply to cross the Elevation saddle into the valley of the Tuamarina River. It descends alongside this river and across the Wairau Plain before reaching Blenheim. SH 1 passes through Weld Pass and Dashwood Pass to enter the Awatere Valley, then countiuses southward before passing Lake Grassmere. From the small town of Ward the highway heads to the coast and follows it to Kaikōura. After passing Kaikōura, it veers inland, twisting tortuously through the Hundalee Ranges before emerging at the northern end of the Canterbury Plains.