This study explores engineering students' enactment of collective agency and perceptions of professional identity. Empirical data were drawn from observation and group interviews with 30 engineering students in a civil engineering course using a problem and project-based learning (PBL) approach. Using the technique of quantifying qualitative data, the study identified patterns of agency manifestation in seven domains within project work: (1) motivation, (2) goal setting, (3) planning, (4) project progression, (5) self-reflection and evaluation, (6) team dynamics, and (7) external support and resources. The study identified a significant correlation between the engineering students' collective agency in these seven aspects of their learning process and their project team outcomes based on group-based project grades. Although students reported many reasons for choosing to study engineering, the majority of the students were found to have a general uncertainty regarding their sense of professional identity, suggesting more activities to support the building of professional competences, such as PBL, should be provided at an earlier stage of engineering curricula.