This qualitative study investigated the impact of explicit instruction, collaborative reflective tasks, and constructive feedback on the criticality of student teachers' (STs') reflections over time. The participants were 26 STs who were engaged in a second language teacher education (SLTE) programme at a research university in Istanbul, Turkey. Data were collected through written reflective reports (n = 26) and a semi-structured interview (n = 13). The findings showed a progression from superficial reflections to more critical reflections (CR) over one semester. Specifically, STs demonstrated more features of improved problematisation, reasoning and deeper analysis ability of their beliefs and practices. In conclusion, this study highlighted that well-planned instructional activities and a supportive learning environment can positively influence the development of STs' CR.