[2] Asan Mugunghwa once again grabbed an opportunity for promotion by winning its second K League 2 title (officially first title after Ansan era), but its owner Korean Police Agency did not recruit new players who could meet clubs' requisite for maintenance before the end of the season.
[3] Runners-up Seongnam FC directly qualified for the K League 1 instead of Asan Mugunghwa, and the third, fourth, and fifth-placed team advanced to the promotion playoffs.
The winners on aggregate score after both matches earned entry into the 2019 K League 1.
FC Seoul won 4–2 on aggregate and therefore both clubs remain in their respective leagues.
Source: K LeagueNotes:† Team played previous season in K League Classic.