 After two seasons as backup to Iñaki Lafuente, he emerged as the side's undisputed starter, helping them qualify to the UEFA Cup in 2004 while extending his contract a further four years.After additional struggles for first-choice duties with Lafuente in the 2005–06 campaign, Aranzubia was definitely deemed surplus to requirements by the Basques after the emergence of Gorka Iraizoz, not appearing even when the first-choice was severely injured during 2007–08 (Athletic received veteran Armando on loan from Cádiz CF, and he became the starter).On 13 July 2008, Aranzubia joined Deportivo de La Coruña on a three-year deal, helping the Galicians to the UEFA Intertoto Cup and starting throughout the entire season, save one match due to suspension.