Antonio Adan was a Real Madrid academy and Spanish youth team mainstay. His meteoric progress during his two season with Real Madrid C were followed by another three with Real Madrid Castilla, during which he was named team captain. Adan traveled with the first team on its 2006/07 US tour, and despite playing for Castilla was officially considered Real Madrid's third keeper. His first team debut took place in a friendly against a combined Palestinian and Israeli team. After his three year stint with Castilla, Adan was officially named a member of the first team. In 2006 he won the Under-19 European Championship in Poland as the starting keeper and team captain.
In 2008/09 the goalkeeper tore his ACL and was sidelined for most of the season. He has made a full recovery and trains regularly with the first team while still acting as the starting keeper for Castilla.