Carson joined Liverpool on a four-and-a-half-year contract and was to provide competition for Jerzy Dudek for a first-team place. He made his first team debut for Liverpool in March 2005 in a defeat to Newcastle United, and made three consecutive appearances in April, including the home leg of the UEFA Champions League quarter-final victory over Juventus. He was an unused substitute when Liverpool were victorious in the 2005 UEFA Champions League Final and 2005 UEFA Super Cup.