2018 Thai League 3

The 2018 Thai League 3 (known as the Omsin League Pro for sponsorship reasons) football season will be the second season of Thai League 3. 31 clubs will be divided into 2 groups (regions).

Promoted clubs
Promoted to the 2018 Thai League 2
 * Samut Sakhon
 * Khonkaen
 * Udon Thani

Promoted from the 2017 Thai League 4
 * BTU United
 * JL Chiangmai United
 * Chiangrai City
 * Muangkan United
 * Marines Eureka

Relegated clubs
Relegated to the 2018 Thai League 4 Northern Region
 * Singburi Bangrajun

Relegated to the 2018 Thai League 4 Western Region
 * Krung Thonburi

Relegated from the 2017 Thai League 2
 * Bangkok
 * Songkhla United

Renamed clubs

 * Banbueng authorize from Phuket City because Banbueng is an absolute football club quota.
 * Bangkok University Deffo was renamed to Deffo
 * Nakhon Si Thammarat Unity was renamed to WU Nakhon Si United

Expansion clubs

 * Songkhla United and Krung Thonburi Club-licensing football club didn't pass to play 2018 Thai League 3 Lower Region. This team is banned 2 years and Relegated to 2020 Thai League 4 Southern Region for Songkhla United, 2020 Thailand Amateur League Bangkok Metropolitan Region for Krung Thonburi.

Withdrawn clubs

 * Amnat United and Phayao were taking a 2-years break. This team is automatically banned 2 years, don't get subsidy and relegated to 2020 Thai League 4 Northern Region for Phayao, 2020 Thai League 4 North Eastern Region for Amnat United.

Third place play-off
This round was featured by Ayutthaya United, the second place of 2018 Thai League 3 Upper Region and Nara United, the second place of 2018 Thai League 3 Lower Region. Winners of third place play-off would promoted to 2019 Thai League 2.

Summary




Matches
Ayutthaya United won 2–1 on aggregate.

Final
This round was featured by JL Chiangmai United, the first place of 2018 Thai League 3 Upper Region and MOF Customs United, the first place of 2018 Thai League 3 Lower Region. Both winners and runners-up would promoted to 2019 Thai League 2 automatically.

Summary




Matches
JL Chiangmai United won 2–0 on aggregate.