2019 Thai League 3

The 2019 Thai League 3 is the third season of the Thai League 3, the third-tier professional league for association football clubs in Thailand, since its establishment in 2017, also known as Omsin League Pro due to the sponsorship deal with Government Savings Bank (Omsin Bank). A total of 28 teams would divided into 2 regions including 14 teams in the upper region and 14 teams in the lower region.

Promoted clubs
Promoted to the 2019 Thai League 2
 * JL Chiangmai United
 * MOF Customs United
 * Ayutthaya United

Promoted from the 2018 Thai League 4
 * Nakhon Pathom United
 * Khon Kaen United
 * North Bangkok University

Relegated clubs
Relegated to the 2019 Thai League 4 Northeastern Region
 * Kalasin

Relegated to the 2019 Thai League 4 Bangkok Metropolitan Region
 * Deffo

Relegated from 2018 Thai League 2
 * Krabi
 * Angthong

Renamed clubs

 * WU Nakhon Si United was renamed to Nakhon Si United

Moved clubs

 * Simork were moved into the Upper Region 2019.

Third place play-off
This round was featured by Phrae United, the second place of 2019 Thai League 3 Upper Region and Ranong United, the second place of 2019 Thai League 3 Lower Region. Winners of third place play-off would promoted to 2020 Thai League 2.

Summary



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Matches
Phrae United won 1–0 on aggregate.

Final
This round was featured by Khon Kaen United, the first place of 2019 Thai League 3 Upper Region and Nakhon Pathom United, the first place of 2019 Thai League 3 Lower Region. Both winners and runners-up would promoted to 2020 Thai League 2 automatically.

Summary



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Matches
Khon Kaen United won 4–2 on aggregate.