A team could only use a maximum of four foreign players in each matchday.
Players in bold joined midway through the competition.
When the first and second round matches were finished as draws, their winners were decided on the regular season rankings without extra time and penalty shoot-outs.
The winners of the second round and the runners-up competed with the tenth and eleven-placed team of the K League 1, respectively, in the final round for the K League 1 spots of the next season.
Suwon Samsung Bluewings won 2–1 on aggregate and therefore both clubs remain in their respective leagues.