This study aimed to examine how peer observation and written reflection could led Pre-Service Teachers (PSTs) in improving the temporal dynamics of their reflection during the Physical Education practicum. Given its dynamic and collaborative nature, an action-research design was conducted throughout an academic year to explore the ongoing and deliberate adaptation of peer observation and written reflection strategies to develop PSTs’ reflection. Six PSTs and the first author, who took on the dual role of external facilitator and researcher, participated in this study. As facilitator, the first author scaffolded the implementation of both pedagogical strategies over the school year. PSTs’ reflections were gathered through semi-structured interviews and reflective journal. Also, additional field notes were gathered by the facilitator during participant observation. The findings showed that an intentional structured combination of peer observation and written reflection helped PSTs to develop their ability to reflect-in-action and to reflect on reflection-in-action. The interaction between peer observation and written reflection enabled PSTs to understand the problems derived from their own pedagogical practice, as well as the need to search for new and better solutions. Doing so, PST started to reflect in an action-oriented and critical way. From a practical standpoint, we recommend that Physical Education Teacher Education programs include the development of a temporal dynamic of reflection not only through peer observation and written reflection, but also using multiple strategies (e.g., audio recordings, video analysis, etc.). By nurturing the temporal dynamic of reflection, PSTs can ongoingly re-examine themselves and their pedagogical intervention critically.