In this article, we consider a previously unidentified form of community of practice: the community of practice of transition. Our exemplar data come from two separate studies, one of a group for trans young people and one of an online divorce support community. Such communities differ from other communities of practice because the transition process itself is the focus and the shared practice of the community. We argue that communities of practice of transition differ from ‘classic’ communities of practice in four main ways. First, and most salient, there are differences in relation to time and its importance. Second, and following from this, there are differences in relation to the focus of trajectories into and through the group, which affect who is able to become a central member. Third, the role and characteristics of central members of the community are different from those found in a traditionally conceived community of practice: moving out of a transitional state (and, therefore, out of the community) is key to old-timer status. Finally, reified events are highly salient in communities of practice of transition, and more important than reified objects. We argue that the concept of a community of practice of transition challenges and expands many of the assumptions underpinning the community of practice as a framework for analysing the dynamics and operation of groups and how identities are forged in and through them. Most significantly, we argue that time needs to be taken more seriously in relation to communities of practice.