General Brazilian
campeonato de futebol júnior
Standard usage in Brazil for youth football competitions
Rio de Janeiro
campeonato de futebol sub-17/sub-20
Often specified by age category (under-17, under-20)
São Paulo
campeonato juvenil de futebol
Frequently uses 'juvenil' instead of 'júnior'
Portugal
campeonato de futebol juniores
Portuguese uses 'juniores' as the plural form