This paper aims to advance our conceptual understanding of design collaboration, a domain-specific subset of collaboration skills that emphasises knowledge-sharing and knowledge-integration processes. This paper explores how design collaboration skills develop along with design expertise across three stages of experience. First-year bachelor students, master students, and design professionals took part in a design game to investigate their design collaboration skills. We assessed their design collaboration skills by analysing their sessions for the degree and quality of knowledge sharing and integration using a reflective practice analysis and an interpretative analysis of their conversation. It was found that the first-year bachelor students and the professionals outperformed the master students in terms of collaborative design performance. In finding this nonlinear relationship, we highlight the need to distinguish between design expertise and design collaboration skills and to treat them as independent concepts when assessing design team performance. Finally, through an interpretive analysis, we developed a typology of design collaboration approaches at the three stages of experience.