The is an electric multiple unit (EMU) commuter train type operated by the third-sector railway operator Tokyo Waterfront Area Rapid Transit (TWR) since 2025. A total of eight 10-car sets are to be built to replace the fleet of 70-000 series sets used on the Rinkai Line since its opening in 1996.
The 71000 series is built by Japan Transport Engineering Company (J-TREC) as part of its "Sustina S24 Series" family of 20-metre-long four-door cars. The type uses a wide-body design to reduce congestion.
Sets are based at Yashio Depot and are formed as follows with six motored ("M") cars and four non-powered trailer ("T") cars.
Passenger accommodation consists of longitudinal seating throughout.
Details of the trains were announced by TWR in November 2023. A total of eight 10-car sets are due to be in service by fiscal 2027.
The first train was delivered from the J-TREC plant in Niitsu in November 2024. Set Z12 followed suit in June 2025.
The 71-000 series fleet entered service on the Rinkai, Saikyà  and Kawagoe lines from 1 October 2025.