Thai League One (formerly Thai Premier League) allows teams to include foreign players with the following rules for the 2018 season:


  • no more than 5 foreign players are allowed on any one club

  • 3 may be from any country

  • one from an AFC (Asian Football Confederation) country

  • one from an ASEAN country (Association of Southeast Asian Nations)

  • on the pitch during a match a team is allowed to use 4 foreign players, which must include the Asian player


Probably the most well known foreigner to play in the Thai Premier League was Liverpool legend Robbie Fowler, who joined SCG Muangthong United in the 2011 season. 


Near the end of the 2015 season, for example, these rules were applied in a conflict between Bangkok United and Bectero Sasana.   (ref)