A total of 14 teams will compete in the league this season.

Three clubs were promoted from the 2018 Thai League 4 Two clubs were promoted to the 2019 Thai League 2 A club was relegated to the 2019 Thai League 4 Northeastern Region A club was relegated from the 2018 Thai League 2 The table lists the positions of teams after each week of matches.

In order to preserve chronological evolvements, any postponed matches are not included in the round at which they were originally scheduled, but added to the full round they were played immediately afterwards.

For example, if a match is scheduled for matchday 11, but then postponed and played between days 12 and 13, it will be added to the standings for day 14.Updated to games played on 8 September 2019Source: Thai League 3 Since 31 March 2019 Simork had suspended.

Source: Thai League 3 Archived 2018-06-12 at the Wayback Machine Note:Unk.1 Some error of T3 official match report 21 August 2019 (Bangkok 2–2 Lamphun Warrior).