Boundary crossing competence is needed to tackle complex problems and should therefore be facilitated in education. The Regional Learning Environment, a typical service learning environment practiced in Dutch life sciences education, offers students ample opportunities to develop boundary crossing competence through multi-stakeholder collaboration, but appears to non-optimally make use of this. This quasi-experimental mixed-methods pre- and post-test intervention study (N=129) investigates the effect of explicit support of student-stakeholder collaboration, by means of workshops, on student-stakeholder collaborative activities and reported boundary crossing learning mechanisms i.e. identification, coordination, reflection, and transformation. The study shows that explicit support of student-stakeholder collaboration in the Regional Learning Environment both stimulates the amount of student-stakeholder collaborative activities, and activates life sciences students' boundary crossing learning mechanisms.