Epistemic agency is increasingly recognised as an important focus in teacher education, yet little is known about how it is enacted when pre-service teachers (PSTs) reflect on learner struggles in Physical Sciences. This qualitative case study investigated how Physical Sciences PSTs enacted epistemic agency through reflective engagement with learner struggles. Situated in a final-year Classroom Research in Physical Sciences module, the study involved 73 PSTs’ written reflections and follow-up semi-structured interviews with eight participants. Data were analysed thematically, guided by the lens of epistemic agency. Findings revealed enactments of critical noticing, representational critique, and responsible pedagogical reasoning, with teacher noticing as a cross-cutting mechanism. The study concludes that structured reflection fosters epistemic virtues and recommends explicit integration of learning struggles and noticing practices in teacher education.