Police in Spain say they have uncovered two separate rings that were allegedly scamming mostly Brazilian families by promising they would turn their sons into elite footballers.
The gangs are accused of selling "false expectations" to families.
The rings charged an initial fee of more than 5,000 euros (£4,400) and then monthly payments of up to 1,700 euros per player, police say.
Around 70 families were scammed and 11 people have been arrested, police say.
Families were told that the money was to cover expenses including tuition fees, housing and paperwork for residency permits in the city of Granada.
But in reality the players "lived in houses... in cramped conditions, with little food and none of them managed to get legal residency" in Spain, the statement said.
Most of the players were Brazilian, aged 16 to 23.
The gangs - which operated independently of each other - split responsibilities, police say.
Some members of the gangs focused on recruitment, targeting wealthy families in their home countries. The second group were involved in educational centres that falsely certified registration so the players could obtain visas.
A third management group oversaw the overall strategy.
The investigation started after one of the players filed a complaint to police.