The initial route opened in October 2011 passed through 6 stations intersecting with three existing lines at Gangnam Station (Line 2), Yangjae Station (Line 3), and Jeongja Station (Bundang Line). Phase 2 opened on 30 January 2016 added 6 stations to the south, extending the line to serve Yongin's Suji-gu and Suwon's Gwanggyo New City. Construction for Phase 3's extension northwards to Sinsa Station started in 2016, with opening slated for January 2022. Construction of the line started in mid-2005, for revenue start in Sep 2011. However, because of the flooding of late July 2011, the opening was delayed and eventually opened on 28 October 2011.