The line is the fourth MRT line to be opened, with the first stage (from Bartley to Marymount stations) commencing operations on 28 May 2009 after delays due to the Nicoll Highway collapse. The next stage to Dhoby Ghaut station was completed on 17 April 2010 and the next stage to Harbourfront opened on 8 October 2011. A two-station extension to Marina Bay station was completed on 14 February 2012. The last stage of the line from Harbourfront to Marina Bay will be completed in 2026, completing the loop.