In the literature on boundaries, it is sometimes falsely assumed that learning naturally evolves from a co-location of diverse practices and perspectives. Empirical studies indicate that this is not self-evident. The aim of this article is to understand the challenge of learning at the boundary. In the light of this aim, the article interprets empirical findings from two previous longitudinal studies of academic projects, in which educational scholars, with diverse cultural backgrounds and different academic perspectives, collaboratively conduct research and encounter boundaries during interaction. The case studies show that (1) boundaries that people encounter can easily stay implicit during ongoing negotiations, and (2) when people do identify boundaries and explicate them during collaborative processes, dialogical engagement is triggered. On the basis of the findings, I argue that explicitly identifying boundaries enables learning since it creates a collective need to take more into account some unfamiliar perspective or practice.