Everyone older than 2 years old will be required to wear face masks throughout the day, the release states. On Tuesday, Six Flags announced its first reopening: Frontier City in Oklahoma City that will open June 5. Six Flags announced new safety protocols, including the requirement of face masks and social distancing, that will be in place at all parks once they reopen. (Six Flags)Six Flags announced new safety protocols, including the requirement of face masks and social distancing, that will be in place at all parks once they reopen. (Six Flags)Six Flags announced new safety protocols, including the requirement of face masks and social distancing, that will be in place at all parks once they reopen.