After just one year, Hierro returned to Europe to sign with Premier League side Bolton Wanderers on the advice of his English teammate at Real Madrid Steve McManaman, and teaming up with another former player of that club, Iván Campo. He scored once during his tenure, which came in a 2–3 loss at Norwich City in December 2004 and, even though hard-pressed by fans and manager Sam Allardyce to stay for a further campaign, he announced his retirement from professional football on 10 May 2005.