In May 2005, while still a member of the under-21 team, Carson was called up to the England senior team squad for the team's tour of the United States later that month. A year later, he came on as substitute for Robert Green, who had suffered a serious injury, in the England B international friendly against Belarus in May 2006. The injury to Green, who had been named in the England squad for the 2006 FIFA World Cup, led to Carson, who was on standby, being promoted to the England squad for the tournament, although he did not make any appearances. Carson continued to be selected for the England senior team squad, and in May 2007, made his second appearance for the England B team in a 3–1 win over Albania. Following the 2007 UEFA Under-21 Championships, he made his full England debut in a friendly against Austria in November 2007 when he kept a clean sheet. A week later, he made his competitive debut in a crucial match against Croatia, replacing Paul Robinson which England lost 3–2, resulting in their failure to qualify for UEFA Euro 2008. Carson was held particularly culpable for the first goal, when Niko Kranjčar cut inside and his dipping speculative shot from 30 yards dipped and bounced in front of him, with Carson only succeeding in parrying the ball into the net as it squirmed through him. England coach Steve McClaren was dismissed the next day, as commentators criticised McClaren for selecting an inexperienced goalkeeper for the match.