Developmental trajectories demonstrate continuities in psychopathology through childhood to adolescence and into early adult life, implying the need for an equivalent continuity in mental health and social care provision. While research, clinical experience and feedback from service users combine to indicate the importance of continuity of care, serious obstacles are found at the interface between services. In this chapter, we discuss the influences impinging upon service user transitions between Child and Adolescent and Adult Mental Health Services. We illustrate how professional communication difficulties, discontinuities in care and user disengagement can co-occur with developmental and life transitions, so heightening the risk of deterioration in mental health and wellbeing at this time. We suggest ways in which service transitions could be managed more effectively so that young people and their families experience optimal transition experiences.