According to the text, Has Thailand been part in the ABU TV Song Festival

Context: The participation of Thailand in the ABU TV Song Festival has occurred twice since the inaugural ABU TV Song Festival began in 2012. Since their début in 2013, the Thai entry has been organised by the national broadcaster Thai Public Broadcasting Service. In 2015, Thailand withdrew from the festival.

Answer: Indeed, Thailand has been participating in the ABU TV Song Festival. It has occurred twice since the inaugural ABU TV Song Festival began in 2012.