 In June 2010, Castillo was named in the 23-man squad of Uruguay for the 2010 FIFA World Cup celebrated in South Africa as the second choice goalkeeper of the national team, being Fernando Muslera the titular goalkeeper.Despite of not making appearances for Uruguay, his team finished fourth in the tournament.The next year, he was nominated in the 23-man of his country for the 2011 Copa América, having the same role during the World Cup in a tournament that Uruguay won.