Accurate modelling of long-term calving behaviour at tidewater glaciers remains a major challenge in glaciology, with existing methods being either overly computationally intensive, or too simplistic to capture observed calving behaviour. Building on previous work that showed the potential of a stochastic positional approach to modelling calving, we investigate how far a stochastic calving model can reproduce observed terminus dynamics and calving behaviour at Store Glacier (Sermeq Kujalleq), West Greenland, with and without coupling to a subglacial hydrology model. We show that the stochastic model is capable of accurately reproducing both qualitative and quantitative dimensions of calving at Store Glacier, while the inclusion of the subglacial hydrology increases calving volumes and produces the observed seasonal calving cycle. We conclude that simple hydrological parameterisations that leave the basal water pressure fixed in time cannot produce the full spectrum of observed calving behaviours of tidewater outlet glaciers.