Due to the COVID-19 pandemic, the season must be postponed to start in late 2020 and end in early 2021.

[2] A total of 11 teams located in Northern, Upper western, and Upper central of Thailand will compete in the league of the Northern region.

[3] In late December 2020, COVID-19 had spread again in Thailand, the FA Thailand must abruptly end the regional stage of the Thai League 3.

[4] The second-placed and the third-placed of the Northern region have the similar points, so they must play-off to find a team to qualified to the national championship stage.

A team can use four foreign players on the field in each game, including at least one player from the AFC member countries (3+1).