Initial teacher education (ITE) programmes in Ireland have seen continued high demand for places, reflecting high regard for the teaching profession. However, there is a dearth of diversity amongst Ireland's student teacher and teaching populations, with the vast majority of entrants to ITE being from majority ethnic groups and a high proportion from higher socio-economic backgrounds. Diversifying the teaching profession has come to be of research and policy significance in recent decades in Ireland. This paper explores issues of retention in ITE in Ireland, with a focus on supporting the engagement and completion of student teachers from under-represented groups. We draw on data collected as part of the "Access to Post-primary Teaching" (APT) project, funded under the Higher Education Authority's Programme for Access to Higher Education (PATH): Strand 1 (Equity of Access to Initial Teacher Education), including interviews with 'working class' student teachers and a focus group interview with teacher educators. While the paper highlights high retention rates in ITE in Ireland, it reports key barriers that particularly negatively impact student teachers from under-represented groups, in relation to identity and belonging, and finance and part-time work. The paper also observes the necessity of a high level of support by programme staff in maintaining high retention rates more generally in ITE programmes. Given the significant barriers student teachers from under-represented groups encounter in ITE, their high levels of retention merits further research, particularly the roles played by their motivation and by the specific additional supports provided by ITE staff and teacher diversity projects.