The Hidaka Main Line is a railway line in Hokkaido, Japan, operated by Hokkaido Railway Company, between Tomakomai Station in Tomakomai and Samani Station in Samani, running along the coast of Hidaka Subprefecture. Services on the 116.0 km (72.1 mi) section of the line beyond Mukawa Station were suspended indefinitely since January 2015 due to storm damage. This section was closed on 1 April 2021 and replaced by a bus service. The closure of this section made the line the shortest in Japan to be classified as a 'main line', at just 30.5 km (19.0 mi), beating the Rumoi Main Line's length of 50.1 km (31.1 mi), which was previously the shortest.

The Hokkaido Railway Company is one of the constituent companies of the Japan Railways Group, and is often referred to using its official abbreviation of JR Hokkaido . It operates intercity and local rail services in Hokkaido, Japan. The company introduced Kitaca, a smart card ticketing system, in autumn 2008.