The 2020 K3 League was the first season of the K3 League as a semi-professional league and the third tier of South Korean football league system. After the 2019 season, the former Korea National League and K3 League Advanced went defunct and rebranded into the K3 League. In the 2020 season, 16 teams are going to compete in the K3 League, and they are 8 teams from KNL, 6 teams from K3 League Advanced, and 2 teams from K3 League Basic. The teams for the 2020 season were announced by the Korea Football Association on 19 December 2019.