Following more than a decade during which the reality of Pannotia was widely accepted, the existence of this Ediacaran supercontinent has come into question. This is due largely to advancing geochronology, which suggests that the supposed landmass had begun to break up well before it was fully assembled. Paleomagnetic data from this time interval have been used to both support and refute the existence of Pannotia, but are notoriously equivocal, and proxy signals of Ediacaran-Cambrian supercontinent assembly and breakup, although collectively compelling, can be individually challenged. Efforts to detect the mantle legacy expected of supercontinent amalgamation, however, are more compelling, and support large-scale mantle upwelling in the wake of Pannotia assembly. So, irrespective of whether Pannotia was a supercontinent or not, its assembly appears to have influenced global mantle convection patterns in a manner consistent with one. In the context of the supercontinent cycle, the question of Pannotia’s existence is of fundamental importance since it is central to the nature, duration and evolution of the cycle, it dictates the cycle’s geodynamic pathway from the breakup of Rodinia to the assembly of Pangea and, more crucially, it queries whether a full-blown supercontinent is needed to drive the cycle from one iteration to the next.