<p>The composite bucket foundations of offshore wind turbines penetrate minimally into the seabed, making local scour a significant threat to wind turbine stability. This study develops a physical model to examine local scour patterns around a novel mono-column composite bucket foundation (MCCBF) under unidirectional flows. The experiments reveal that under weak-flow conditions, no significant scour pits develop at the front or lateral sides of the MCCBF, while two distinct scour pits form behind the lateral sides. Under strong-flow conditions, substantial scour pits emerge at both frontal and lateral sides of the bucket foundation, with two scour pits extending downstream on either side. The research demonstrates that both the range and depth of local scour increase with higher flow velocity and decreasing water depth, though the mechanisms influencing local scour around the MCCBF prove more complex than those affecting monopiles. The distinctive structural features of the MCCBF necessitate particular consideration of effects related to bucket foundation exposure. The study concludes by proposing an empirical formula for predicting maximum scour depth around the MCCBF.</p>