In recent years, policy in Ireland has emphasised the importance of early childhood education, and there has been an increasing focus on the inclusion of mathematics (numeracy) in early childhood settings. This research explored how one Irish preschool setting guided and supported children’s engagement and interest in mathematics during their final year of preschool (ages 4-5 years). This detailed study of practice contributes to the current small body of knowledge of preschool mathematics education in Ireland. Adopting a micro-ethnographic approach, qualitative data were generated using a range of data collection methods (participant observation, semi-structured interviews, reflective conversations and autophotography). Findings indicate a disconnect between pedagogical strategies to support early mathematics highlighted in setting policy documents, such as Math Talk, and those enacted in the preschool classroom. The analysis shows that educator beliefs around non-intervention in children’s free play influenced practice. This resulted in inequitable opportunities to explore mathematics, for example, girls’ limited opportunities to engage in block play. Beliefs about children and mathematics deemed part of primary school curricula also limited support given at times, for fear of overpreparing children for primary school. Analysis reveals that the incorporation of mathematics into adult-led activities, such as circle time, was not cognitively challenging for some children at the time of the study. Findings also highlight the impact of children’s non-attendance and children with English as an Additional Language, requiring further support. The study recommends that mandatory initial professional training and professional development focused on pedagogical strategies, such as Math Talk, strategies to support EAL children, and the necessity to engage with a wider variety of mathematical concepts other than number and measures.