Japan National Route 338

National Route 338 begins at an intersection with National Route 5 in central Hakodate 150 meters (490 ft) east of Hakodate Station as part of an unsigned concurrency with National Route 279. The highway travels southwest along city streets through the city, then curves to the northwest, and turns northeast towards the former site of the city's ferry terminal, which was moved to the northwest of Hakodate Station. The highway's brief 1.8 kilometers (1.1 mi) route in Hokkaido ends at the former terminal, which has since been converted into a retail area.[2] Aside from the last 100 meters (330 ft) of the highway near the ferry terminal, the highway also carries the Main Line of the Hakodate City Tram in its median.[3]

The highway is next carried south across the Tsugaru Strait via the Tsugaru Kaikyō Ferry to Ōma on the northern tip of Aomori Prefecture's Shimokita Peninsula. From the route's northern terminus in Hakodate to Ōma, National Route 338 runs concurrent with National Route 279; however, in Ōma, National Route 279 leaves the concurrency, travelling southeast towards Mutsu while National Route 338 heads south towards the village of Sai. After passing through Sai, the highway enters the western edge of Mutsu and turns east towards the center of the city.

In Mutsu, national routes 279 and 338 briefly meet again, sharing a short concurrency. After leaving the concurrency, National Route 338 continues its path southeast across the peninsula while National Route 279 heads south towards Noheji at the southern base of the peninsula. National Route 338 parallels the Pacific coast for the rest of its route south through Higashidōri, Rokkasho, and Misawa before terminating in Oirase.[4]