Several competition authorities have declared that they are willing to use competition law for forcing companies to give third parties access to data collected by them. Enforcing such access obligations is, however, challenging where the data in question is personal data. Based on three case studies, Bird & Bird partners, Anne Federle (competition law) and Benoit Van Asbroeck (IT & data protection), explore in this article whether and how companies can obtain access to personal data collected by another market player.