The 2025 season is FC Seoul's 42nd season in the K League 1, the top tier of South Korean football. The club also participates in the 2025 edition of the Korea Cup and in the 2025–26 AFC Champions League Elite.
Transfers.
Pre-season.
In.
Transfers in
Returned from loan
Out.
Transfers out
Loaned out
Loan return
Mid-season.
In.
Transfers in
Loan Return (In).
Transfers in
Out.
Transfers out
Loaned out
Loaned return
Competitions.
K League 1.
Matches.
As usual, the league season is played over 38 matches. After 33 league matches between the 12 participating teams, the teams are split into the final round (top 6 teams) and relegation round (bottom 6 teams).