The line between Sijiqing Qiao and Dongbabei opened on December 15, 2024.

Line 12's route has undergone substantial changes on the planners' drawing board.

In the late 1990s, one draft of the subway plan showed Line 12 running from the Beijing South railway station to Huangcun.

[8] The Beijing South railway station was then built with subway platforms for only Lines 4 and 14.

[9] In June 2012, there were several media reports listing the planned stations of the line.