On maps, diagrams and signboards, the line is shown using the color emerald (previously coded "teal"), and its stations are given numbers using the letter "N".

Under an agreement between Tokyo Metro and the Tokyo Metropolitan Government, the fare for this section is calculated on the Toei fare system for passengers traveling to stations on the Mita Line past Shirokane-Takanawa, on the Metro fare system for passengers traveling to stations on the Namboku Line past Shirokane-Takanawa, and on the system "most beneficial to the passenger" (presently the Metro schedule) for travel solely on the shared sector.

The Namboku Line was inherited by Tokyo Metro after the privatization of the Teito Rapid Transit Authority (TRTA) in 2004.

[4] Effective the timetable revision on 18 March 2023, through services onto the Sagami Railway commenced courtesy of the Tokyu and Sotetsu Shin-Yokohama Line.

On 28 January 2022, Tokyo Metro announced that a 2.5 km (1.6 mi) spur line from Shirokane-takanawa to Shinagawa would be built.