Thai League 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.