Kasetsart FC
Chainat FC
Ayutthaya United
Rayong FC
Customs United
Trat FC
Nakhon Pathom FC
Krabi FC
Suphanburi FC
Samut Sakhon
Sisaket FC
Army United FC
Bangkok FC
Uthai Thani FC
Raj Pracha
Air Force Central
Thai Honda
Ang Thong FC
PTT Rayong
Nakhon Ratchasima
Sukhothai FC
Chonburi
Samut Songkhram
Prachuap FC
BBCU
Chamchuri Utd
Bangkok Christian College
Krung Thonburi FC
Looktabfah FC
Hua Hin City
Nonthaburi FC
Assumption United
Air Force Robinson FC
Samut Prakan FC
Rangsit FC
Ayutthaya FC
Dome FC
Chiangrai City FC
Sinthana Kabinburi
Patum Thani Utd
Look Isan FC
Pathum Thani Seeker
Saraburi TRU
Phan Thong FC
Tak City FC
Rajapruek Muangnont
Chumphon FC
BTU United
Prachinburi United
Thonburi City FC
Thai League 2 (Thai: ไทยลีก 2), commonly known as the T2, formally called Thai Division 1 League, is the second-tier professional league in the Thai football league system. Seasons typically run from August to May, with each team playing 34 games : two against each other team, one home and one away. It is sponsored by BYD Auto and therefore officially known as the BYD Seal 5 League II. Champion, runner up and teams ranked 3rd – 6th qualified in play off for last spot in top tier promoted to Thai League 1 at the end of the season, whilst three are relegated to Thai League 3.
For the 2008 season, the Football Association of Thailand (FAT) reduced the number of teams in the league to 16 teams. Previously there had been two groups of 12 clubs. For the 2011 season the number of teams was increased to 18 teams, The Thai Division 1 League is a season run from March to October, with teams playing 34 games each totalling 306 games in the season. In 2016, the Khǒr Royal Cup became a trophy for Thai Division 1 League. In 2017 the Football Association of Thailand changed the name to Thai League 2.