Xabier 'Xabi' Castillo Aranburu (born 29 March 1986) is a Spanish former professional footballer who played as a left-back.
Born in Durango, Biscay, Castillo came up through the ranks at Athletic Bilbao, but made his senior debut with Basque neighbours Real Sociedad, where he had finished his football development.
[1] His first professional experience came with UD Las Palmas on loan, in 2006–07's Segunda División.
On 15 July 2009, Castillo returned his first alma mater and signed a four-year deal.
[4] Castillo spent the entire 2011–12 on the sidelines, due to a patellar ligament injury.