Fans will be allowed to cheer during Thailand's November 15 World Cup qualifier against Australia in Bangkok, after the government eased strict mourning rules in place since His Majesty King Bhumibol Adulyadej's passing.
Uncertainty has surrounded the qualifier since the king's October 13 death plunged the country into a period of deep mourning.
Sports events, concerts and even televised soap operas have been cancelled, with bars and nightclubs closing early and avoiding loud music.
The Football Association of Thailand (FAT) agreed to host the game as planned but had ordered fans to stay muted in keeping with a sombre national mood.
But on Wednesday the FAT relaxed the rules following guidance from the ruling junta, which said entertainment activities can start returning to normal after a 30-day mourning period.
"Football fans who attend the match can use cheering equipment, show symbols and cheer," FAT deputy general secretary Patit Suphaphongs wrote in a Facebook post.
Thailand's "ultra" fans are renowned for using horns, drums and boom sticks in well-choreographed shows of support for the national team.
Patit advised fans to "dress in an appropriate" way but did not elaborate.
Australia are currently second in Group B of final Asian qualifying for a place at Russia 2018, while Thailand are desperate for a win after failing to earn a point after four games.
The FAT has already cancelled the remainder of the domestic football season and said league rankings on October 14 will determine the champions and relegation candidates.