The Seibu Yūrakuchō Line is an underground railway line operated by the private railway operator Seibu Railway in Japan. The line links the Seibu Ikebukuro Line at Nerima Station with the Tokyo Metro Yūrakuchō Line and Tokyo Metro Fukutoshin Line at Kotake-Mukaihara Station in Nerima, Tokyo.

The S-Train is a reserved-seat Commuter Liner train service operated mainly by Seibu Railway, along with Tokyo Metro, Tokyu Corporation, and Yokohama Minatomirai Railway.