The transition from primary to post-primary school is a crucial time in a student’s journey as a mathematical learner. While this transition has been widely studied, much of the existing research, particularly in the Irish context, has focused on tracking mathematical performance or gathering insights from teachers. Little is known about what happens to students’ mathematical identities during this transition. This qualitative longitudinal study sought to address this gap, foregrounding student voice and examining their mathematical identity journeys. Using a sociocultural theoretical lens, the research conceptualises mathematical identity as fluid, socially constructed and narratively expressed. 17 students were followed over an 20-month period, with their experiences captured through semi-structured interviews and personal journey graphs. A dual analysis was employed; the Listening Guide was used to conduct a voice-centred analysis of three illustrative student narratives, while thematic analysis was applied to data from all 17 students. The findings highlight the transition as a multifaceted process involving overlapping “mini-transitions” that often extended beyond First Year. It emerged as a period of significant identity negotiation marked by confidence, doubt and adjustment, as students navigated through a complex array of changes. A pattern of silent acceptance emerged, with many students quietly adjusting to distinct changes in their learning experiences without voicing discomfort. Key influences on their identity included the role of the teacher, assessment practices, peer comparisons and learning continuity. The study contributes to growing research on mathematical identity by illuminating its relational nature. It shows how students reconfigure their sense of self as mathematics learners in response to social and institutional shifts. The research calls for responsive pedagogies and more holistic transition supports that recognise identity work as central to mathematics learning. It calls for educational policies that foreground student voice and position mathematical identity alongside mathematical achievement in terms of importance.