As the 2018 FIFA World Cup start on 14 June, the last round before stoppage will be held on 19–20 May.
Players name in bold are registered during the mid-season transfer window.
The exact matches are determined upon the league table at the time of the split.
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.