The only connection to any other rail line is a rarely used maintenance connection to the JR East Chūō Main Line (just west of Musashi-Sakai Station) that is used to transfer trains requiring inspection or major repairs to Seibu's Musashigaoka Vehicle Inspection and Repair Shop.

The Seibu Tamagawa Line is single-track: trains traveling in opposite directions pass each other as necessary at the stations, which are double-track.

All services on the Seibu Tamagawa Line are Local trains, stopping at all stations.

Since March 2010, the line's services are operated exclusively by a fleet of 4 x 4-car New 101 Series trains.

By request from a questionnaire at the 100th-anniversary event of the Tamagawa Line, from January 24, 2018, Seibu Railway's old livery "Akaden Paint" (red x beige) was used.

This livery was the most requested after Akaden painting in the questionnaire at the 100th-anniversary event of Tamagawa Line.