Relegated from K League Classic Promoted to K League Classic Newly joined Withdrawn Note: Flags indicate national team as has been defined under FIFA eligibility rules.

The winner on aggregate score after both matches earned entry into the 2018 K League 1.

Sangju Sangmu won 5–4 on penalties and therefore both clubs remain in their respective leagues.

Attendants who entered with free ticket were not counted.

Updated to games played on 29 October 2017Source: K League ClassicNotes:† Team played previous season in K League Classic.