The San'in Main Line (山陰本線, San'in-honsen) is a railway line in western Japan, which connects Kyoto and Shimonoseki, Yamaguchi, operated by West Japan Railway Company (JR West). It is the major railway line of the San'in region, approximately paralleling the Japan Sea, crossing Kyoto, Hyōgo, Tottori, Shimane, and Yamaguchi prefectures. The main portion from Kyoto to Hatabu is the longest single continuous railway line in Japan at 673.8 km (418.7 mi), although no regularly scheduled train operates over the entire line.

The section between Kyoto and Sonobe, connecting Kyoto and its northern suburbs, is a part of JR West's Urban Network and is nicknamed the Sagano Line.

This section is designated the letter "E".

Rapid trains are operated as local trains and stop at every station between Sonobe and Fukuchiyama.

For Limited Express Maizuru, Hashidate, Kinosaki, Kounotori and Hamakaze stopping patterns, please check their respective articles.

This section is designated the letter "A".

For Limited Express Hamakaze, Super Hakuto, Super Inaba, Super Oki and Super Matsukaze stopping patterns, please check their respective articles.

This section is designated the letter "D".