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.
After Army United FC announced its dissolution in the end of the season, Ranong United was choose as the third team to promoted to Thai League 2.
Promoted to the 2019 Thai League 2
Promoted from the 2018 Thai League 4
Relegated to the 2019 Thai League 4 Northeastern Region
Relegated to the 2019 Thai League 4 Bangkok Metropolitan Region
Relegated from 2018 Thai League 2
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.
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Phrae United won 1âÂÂ0 on aggregate.
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.
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Khon Kaen United won 4âÂÂ2 on aggregate.