The aims of this article are to describe the ongoing development of adolescent and young adult (AYA) cancer services within the European Union (EU), and to develop consensus on key areas within the field. This survey used an e-Delphi design. An initial survey was distributed via email to professionals working in Europe. A snowball sampling technique was used to promote distribution. Consensus was sought over three rounds from October 2012 to April 2015. Consensus was defined as >80% agreement ("agree" or "strongly agree"). Sixty professionals participated in round 1, 106 in round 2, and 61 in round 3. Twenty-six countries were represented across all rounds. Consensus was achieved for: the need for national policy guidance, the importance of patient choice, the validity of the International Charter of Rights for Young People, and some aspects of multi-disciplinary working. There was 75% agreement on a single definition of the patient age range within AYA cancer care. European professionals with expertise in AYA cancer care reached consensus on key elements of care for this group. The optimal AYA age range remained an elusive topic on which to agree. The broad engagement and interest in AYA cancer across the EU through the European Network for Cancer in Children and Adolescents (ENCCA) network was also demonstrated.