The standard gauge line branches off the Buchloe–Lindau railway in Immenstadt and runs via Sonthofen to Oberstdorf.

The 13.38 km long line from Sonthofen to Oberstdorf was opened by the Lokalbahn AG (LAG) company on 29 July 1888.

With the nationalisation of the LAG on 1 August 1938, the Deutsche Reichsbahn became responsible for the entire route, which was now administered by the Reichsbahndirektion Augsburg.

[3] The construction of the new Sonthofer station commenced on 15 November 1937, but was delayed due to the war and was not recommenced until 30 August 1948.

[4] The old Sonthofen station building—it was located on Promenadestraße, opposite the junction with Schnitzerstraße—was demolished in 1962 as part of the redevelopment of Oberallgäuer Platz.

The offer is supplemented by individual services that only run between Kempten or Immenstadt and Oberstdorf.