When projects are used in traditional classes, students are often expected to learn professional skills such as project management or communication along with technical skills. But often only technical skills are explicitly addressed and discussed. In this coffee&LEARN session, the presenting team will talk about their recently published study which aimed at assessing professional skills. The team examined which professional skills were students developing in team-based design projects in mechanical engineering in the context of Bachelor's and Master's courses. The results highlight features of projects that seem to support student learning of professional skills more effectively than others.