It runs from Teltow in the district (Kreis) of Potsdam-Mittelmark via Südkreuz, through the Berlin Nord-Süd Tunnel with a stop at Friedrichstraße, and ends in Blankenburg in the borough of Pankow.

On weekends the S26 runs from Teltow to Potsdamer Platz.

[1] The current service began operation in December 2017.

The S26 designation was previously used for several short-lived services: The current S26 began operation on 10 December 2017 between Teltow Stadt and Waidmannslust; it replaced the S85 north of Bornholmer Straße.

[8] The northern terminus shifted from Waidmannslust to Berlin-Blankenburg on 10 December 2023.