Forecasting the potential position of future eruptions is fundamental for managing volcanic hazards. Here, we develop a new approach to identify the most likely positions for future eruptions based on the propagation path of the magma that fed past eruptions. Its application to Campi Flegrei shows probability peaks at 2 and 4 km from the caldera center and in the direction of existing topographic peaks. High probability areas correlate well with caldera’s structure and recent major seismicity.