The Tsugaru-Kaikyō Line (津軽海峡線 Tsugaru-Kaikyō-sen?) was a railway line in northern Japan linking Aomori Station in Aomori and Hakodate Station in Hokkaido.
The Tsugaru-Kaikyō Line was actually made up of portions of four separate lines: the Tsugaru Line, operated by East Japan Railway Company, and the Kaikyō, Esashi, and Hakodate Main lines, operated by Hokkaido Railway Company. The name was created following the opening of the Kaikyō Line and Seikan Tunnel on March 13, 1988.
The line name is out of use since March 26, 2016 when the Hokkaido Shinkansen opened and replaced regular passenger services connecting Aomori and Hakodate on the Tsugaru-Kaikyō Line. The railway lines that formed the Tsugaru-Kaikyō Line continue to operate freight and passenger trains except for passenger trains on the Kaikyō Line section.