2018 Thai League 3 Lower Region

2018 Thai League 3 Lower Region is the 2nd season of the Thai football league. It is a part of the Thai League 3 and the feeder league for the Thai League 2. A total of 14 teams will compete in the league this season, after Banbueng withdrew before the season started.

Promoted Clubs
A club was promoted from the 2017 Thai League 4
 * BTU United

A clubs was promoted to the 2018 Thai League 2
 * Samut Sakhon

Relegated Clubs
A club was relegated to the 2018 Thai League 4 Western Region
 * Krung Thonburi

A club was relegated from the 2017 Thai League 2
 * 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.

Foreign players
A T3 team could registered five foreign players by at least one player from AFC member countries and at least one player from ASEAN member countries. A team can use four foreign players on the field in each game, including at least one player from the AFC member countries or ASEAN member countries (3+1). ↔: players who have dual nationality by half-caste or naturalization.
 * Note :
 * players who released during summer transfer window;
 * players who registered during summer transfer window;

Top scorers

 * As of 26 August 2018.

Attendance by home match played
Source: Thai League 3

Note: Unk.1 Some error of T3 official match report 28 July 2018 (Trang 3–1 Ranong United).

Unk.2 Some error of T3 official match report 5 August 2018 (Nara United 7–0 Simork).