CAS clears Ecuador to play at World Cup
CAS ruled that Castillo was eligible to play but sanctioned the Ecuador federation (FEF) for the "falsification" of his passport.
"The Court of Arbitration for Sport (CAS) confirms the eligibility of the player Byron Castillo (Ecuador) but imposes sanctions against the Ecuadorian football federation for a violation of the FIFA regulations," the court said in a statement.
The ruling ends several months of a battle started by Chile and Peru to displace Ecuador who finished fourth in South American World Cup qualifying to secure the last automatic regional berth.
They have been drawn in Group A alongside hosts Qatar, the Netherlands and Senegal.
Peru finished fifth and lost a playoff to Australia. Chile ended up seventh, five points behind Ecuador.
The complaint centred around Castillo who played in eight of Ecuador's qualifiers, including both games against Chile.
The Chilean football federation (FFCH) said there was evidence that Castillo, who plays for Leon in Mexico, was born in Colombia in July 1995 and not in Playas, Ecuador in November 1998.
The FFCH alleged "use of a falsified birth certificate, false declaration of age and false nationality".
The claim was dismissed by FIFA in September, prompting the case to go to CAS who "partially upheld the appeals and set aside the decision of the FIFA Appeal Committee".
However the court crucially concluded that Castillo was eligible, regardless of his birthplace, because "Ecuadorian authorities acknowledged Byron Castillo as an Ecuadorian national".
The panel, though, was "comfortably satisfied that the player’s date and place of birth were incorrect since the player was actually born in Tumaco, Colombia, on 25 June 1995", leading CAS to hold the FEF "liable for an act of falsification".
Ecuador will have to pay a fine of 100,000 Swiss francs (100,650 euros) within 30 days, and the national men's team will begin "with three penalty points" for the qualifying campaign for the 2026 World Cup, co-organised by the United States, Mexico and Canada.