This paper is based on a user-centric innovation project, Free2Ride, which is seen as an example of community interaction that overcomes boundaries. The Free2Ride projects goal was to develop a piece of ICT safety equipment consisting of a sender (on the horse) and a receiver (application in a smartphone) to be used by equestrian club members during their everyday riding activities. We will answer the research question of what the characteristics of a boundary dialogue in user-centric innovation activities are. The aim of the paper is to propose a model describing the characteristics of boundary dialogue in user-centric innovation that involve different communities of practices such as ICT developers, users and researchers. An important element of that model is the mental wandering, inwards and outwards, by core members in a community. We discuss the temporal as well as the symbolic nature of the mental wandering during the boundary dialogue in user-centric innovation activities. We applied a combination of research approaches consisting of action research and engaged scholarship approach. The theoretical framework for analyzing our findings is communities of practices with a specific interest in boundary spanning and learning dialogues.