This study is set up to investigate the effect of Digital Twins on service business model innovation. In other words, what effect do digital twins bring to existing service business models? A two-phases exploratory research was set up to understand this research enquiry. Phase One focused on the overall understanding of how DT are set, implemented and used. 37 interviewees across three large industrial engineering firms, in addition to two DT platforms architects. Phase Two focused on the study of the context of the use and effect on the firms’ service business models on three pairs of cases. Our research shows four generic types of service business models founded on the DT platform and their trajectories.