[9] If the reserve team finished in the bottom half of their region's league table, they would be suspended in the next season.
Meanwhile, the last placed (except reserve teams) of each regions will relegate to the 2020 Thailand Amateur League.
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 and runners-ups of the upper and lower groups would promoted to the 2020 Thai League 3.