Regional stage
The number of teams in 6 regions including 11 teams in the Northern region, 11 teams in the Northeastern region, 12 teams in the Eastern region, 12 teams in the Western region, 12 teams in the Southern region, and 14 teams in the Bangkok metropolitan region. The winners and runners-up of each region will advance to the national championship stage to finding 3 teams promoted to the 2021–22 Thai League 2. In late December 2020, the COVID-19 had spread again in Thailand, the FA Thailand must abruptly end the regional stage of the Thai League 3.Northern region
:League tableNortheastern region
:League tableEastern region
:League tableWestern region
:League tableSouthern region
:League tableBangkok Metropolitan region
:League tableNational championship stage
The national championship stage is the next stage from the regional stage. 1st and 2nd places of each zone qualified for this stage by featured in 2 groups. Teams from Northern, Northeastern, and Eastern regions would have qualified to the upper group. Meanwhile, teams from Western, Southern, and Bangkok Metropolitan regions would have qualified to the lower group. Winners, runners-ups, and third-placed of the national championship stage would be promoted to the 2021–22 Thai League 2.Play-off round
, - !colspan=3, Northern region , - !colspan=3, Bangkok metropolitan regionGroup stage
:Upper region :Lower regionKnockout stage
:Third place play-offTeams promoted to 2021–22 Thai League 2
:* Lamphun Warriors (champions)See also
* 2020–21 Thai League 1 * 2020–21 Thai League 2 * 2020–21 Thai League 3 Northern Region * 2020–21 Thai League 3 Northeastern Region * 2020–21 Thai League 3 Eastern Region * 2020–21 Thai League 3 Western Region * 2020–21 Thai League 3 Southern Region * 2020–21 Thai League 3 Bangkok Metropolitan Region * 2020–21 Thai League 3 National Championship * 2020–21 Thai FA Cup * 2020 Thailand Champions CupReferences
External links