General Brazilian
torneio de futebol juvenil
Most common usage across Brazil
Rio de Janeiro
campeonato de futebol de base
Often uses 'futebol de base' (grassroots football)
São Paulo
torneio de futebol infanto-juvenil
May specify age categories more explicitly
Portugal
torneio de futebol juvenil
Same as Brazilian, though 'futebol' is more commonly used than 'soccer'