The long-term (decades) evolution of shoreline change along coastline (O(15)Km) with complex offshore wave transformation challenges both, state of the art process-based morphodynamics and reduce-complexity shoreline models. A major limitation is the computational time required to simulate the detailed spatiotemporal evolution of the wave field, particularly in regions where offshore wave refraction induces localized energy focusing. This study focuses on a 15-km sandy coast on the North Medoc, southwestern France, characterized by high-energy, macro-tidal conditions, severe erosion, and complex offshore bathymetry. Effective coastal management strategies for the coming decades require the implementation of a reduced-complexity (RC) shoreline model. However, oversimplification of wave transformations in such a complex hydro-morphodynamic environment can result in flawed predictions of alongshore wave-breaking parameters and, consequently, shoreline change. Thus, a full wave propagation model is required, but computational time reduction techniques must be implemented to minimize computational cost. To address these challenges, this study introduces an easy-to-apply input reduction (IR) methodology that integrates offshore wave clustering to reduce computational costs when modeling long-term shoreline change within RC shoreline models.