Being members of a league at a particular level also affects the eligibility for Cup competitions.
In 1996 season, The Thai Premier League, The top level of football league was constituted by Football Association of Thailand rather than Kor Royal Cup.
Until the 2009 season, the number of teams from all leagues in the High division will consist of 16 clubs.
However, in the 2009 season, FAT needed to develop the Thai football league system and specify the quality of the team in high-division for conforming to AFC regulation.
Consequently, they determined to adjust the Division 2 competition form by combining it with Provincial League and dividing Division 2 league into 5 regions (Bangkok and perimeter, Central and Eastern, Northern, North-Eastern, and Southern).