In December 2003, Neuner won the German Cup for 17-year-olds, which led to her appointment for the 2003–04 European Cup competition for juniors. With four wins at European level, Neuner qualified for the 2004 Junior/Youth World Championships in Haute Maurienne, France, where she won the sprint and relay events, as well as silver in the pursuit. One year later at the 2005 Junior/Youth World Championships in Kontiolahti, Finland, she claimed two silver medals (pursuit and relay), and again won the sprint discipline. With her success at junior level, Neuner at 18 years old, was considered one of Germany's biggest biathlon talents ever. Even before achieving any results at senior level, she had signed a sponsorship deal.