<p>This study examines the hydrodynamic performance of a box-type floating breakwater equipped with front and rear perforated vertical skirt plates for wave force attenuation. Utilizing linear potential wave theory and the Boundary Element Method, the research compares various fluid–structure interaction models through perforated plates, focusing on linear and nonlinear pressure drop formulations. Validation against available experimental data for fixed perforated cylinders shows that nonlinear (quadratic) pressure drop models yield more physically consistent predictions. The validated quadratic model and the traditional linear model are utilised for investigating wave-induced forces, structural motions, and transmitted wave fields for the floating breakwater with vertical skirt plates. It is found that the incorporation of porosity in the skirt plates significantly reduces excitation forces and peak heave motions as compared to impermeable designs. Additionally, the perforated configuration demonstrates superior wave attenuation relative to traditional box-type breakwaters. These findings support the effectiveness of perforated skirt plates in enhancing the performance of floating breakwaters in mitigating wave actions and reducing structural motions. It is also found that the linear pressure drop models produce consistent trends relative to the more accurate quadratic model, with deviations of approximately ± 15% in predicted wave-induced forces, structural motions, and transmitted wave fields.</p>