Modular floating structures (MFS) emerge as a sustainable solution for creating additional useable spaces in the marine environment. However, positioning MFS near the coast can harm the natural sedimental balance and coastal morpho-dynamics. The environmental impact of floating structures on sediment transport can be evaluated with numerical models that rely heavily on structure-specific transmission coefficients as one of their primary inputs. Using an XBeach model, the current research examines the effect of a multimodule floating seawall configuration on the natural sedimental balance off the eastern Mediterranean coast. The current study uses surveyed bathymetry and over 30 years of measured wave data to detail the environmental condition of the model. In addition, the specific transmission coefficients of the floating seawall used in this research are obtained through physical testing. Although the current research is site-specific, the results from this study can help optimize the distance of the MFS from the adjacent coastline to minimize effects on the sediment balance or to be used as part of a coastal protection scheme.