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

In addition, the Thai League 4 had combined with the Thai League 3 and compete as Thai League 3 since this season[1] and there is no relegation in this season.

[2] A total of 12 teams located in Eastern of Thailand will compete in the league of the Eastern 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.

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).