Teacher recruitment and retention concerns across the world remain a high priority to ensure the best possible education opportunities for children and young people. Related to recruitment and retention, but also important in its own right, is the wellbeing of early career teachers. This study investigated the wellbeing of early career teachers in England and Australia to examine how best to provide early career support as a foundation for professional growth and longer-term retention. Survey responses from 67 newly qualified teachers in England and Australia, and five semi-structured interviews, provided rich insights into new teachers' experiences, highlighting the overwhelming nature of the transition experience as new teachers struggled to adjust as they moved from the relative safety of the initial teacher education context to the reality of work in schools, in particular managing considerable workload which continued beyond the initial transition phase. Vital to successful transition were ongoing linkages between initial teacher education providers and employing schools, a supportive community of practice and bespoke mentoring. This has important policy implications, emphasising the need for personalised approaches to transition with high-quality mentoring during the first few years in the profession. An 'educate - mentor - nurture' model is proposed, to enable smoother and more supportive transitions, leading to professional growth and wellbeing.