This study followed three preservice student teachers as they navigated a semester-long infant-toddler practicum designed to enact a relationship-based approach to teaching and learning. Selected participants were in particular and contrasting placement settings, which served as a catalyst for engaging in critical reflection in multiple ways. Critical reflection was integrated into all course assignments and highlighted within an interactive journaling process. Throughout the practicum, students met together in a weekly seminar with the course instructor, who also served as their field supervisor. Findings uncover multiple ways that critical self-reflection was stimulated in preservice students and the value and interconnection of multiple mentoring practices, including traditional, collaborative, peer and reverse mentoring. While each preservice student teacher engaged in critical reflection in unique ways, they all benefitted from the supportive infrastructure and socially shared, collective reflection with others. This study highlights how critical reflection supported by collaborative dialogue and mentoring can influence transformative practice in caring for infants. Implications for early childhood teacher education and insights for the field are discussed. (author abstract)