The 41.3km Line S1, which is part of the third phase of the Suzhou metro network, will run east from Yiting Road station in Suzhou Industrial Park to Kunshan City and Kunshan Huaqiao, which has been served by Shanghai metro Line 11 since October 2013.

Services on the 28-station line will be operated by a fleet of six-car Type B metro trains, which will operate at up to 100km/h.

Trial passenger services are expected to begin in December 2023.

Shanghai Shentong Metro Group announced in November that it has signed a partnership agreement with metro operators in Hangzhou and Ningbo which enable users of the Shanghai Metro app to travel on metro networks in other cities in the Yangtze River Delta.