In July 2005, Tacchinardi was transferred to Villarreal CF who signed him on one-year loan from Juventus, following the appointment of Fabio Capello, who took over the managerial position from Marcello Lippi, and also due in part to the purchases of Patrick Vieira and Federico Balzaretti. He became an integral part of the starting XI for the club, helping the team to reach the UEFA Champions League semi-finals. He returned to Juventus on 30 June 2006, but following the Calciopoli troubles he extended his loan for one more year, in July 2006. His loan finished at the end of the 2006–07 season, in which he appeared for the club in more than 50 official matches, scoring 3 goals. He returned to Juventus again in the summer of 2007, and it was believed that he would remain at the club, following the appointment of Claudio Ranieri and the club's new start, however his contract was mutually terminated in August 2007, following certain unspecified disagreements with the club's new board of directors.