To ensure the geotechnical stability and operational safety of jack-up structures in offshore energy infrastructure, it is crucial to comprehend seabed scour surrounding spudcans. In this study, scour development and soil-structure interaction around spudcans with different geometries are experimentally investigated in three dimensions. Scour tests were conducted on models with varying diameters and conical angles to examine the effect of geometry on spudcan behaviour. The findings show that localised scour beneath the footing is exacerbated by a decrease in conical angle, which may increase vertical erosion and reduce bearing capacity. On the other hand, spudcan diameter has a limited impact on the normalised scour depth but has a significant influence on the absolute scour depth and controls the horizontal extent of seabed disturbance. The 3D scour development analysis also shows that spudcan diameter largely controls the scour area, or the zone of sediment displacement in the x-y plane, while sharper cones result in deeper, more localised soil removal. With regard to foundation design, positioning methods, and risk mitigation in the offshore jack-up sector, these findings offer essential insights into the response of seabed under combined hydrodynamic and structural loading.