The present study focuses on wave trapping due to the submerged horizontal porous plate combined with the bottom-standing porous structure and surface-piercing porous structure. The submerged plate thickness is considered to be negligible as compared to the incident wavelength and water depth, and the porous structure is considered to be of finite width. The study is performed based on the eigenfunction expansion method, and the wave interaction with the combined structure is investigated using the small amplitude wave theory. The orthogonal mode-coupling relation is used to analyze the wave interaction with the combined structure. The reflection, transmission, and dissipation coefficients along with wave force on the porous structure are investigated to analyze the hydrodynamic performance of the composite porous breakwater system. Further, the effect of porosity of submerged plate and structure, submergence depth of plate and structure, angle of incidence, and the submerged plate length are investigated to analyze the effective wave dissipation by the composite breakwater. In addition, the comparative study of the numerical method is performed with the results available in the literature. The study noted that the wave damping due to the submerged porous plate backed by surface-piercing porous structure is more as compared to the submerged porous plate backed by the bottom-standing porous structure. The study performed will be helpful to scientists and engineers in the design of suitable composite breakwater systems and also assists in selecting the best structural configuration for attenuation of wave height and to protect the offshore facility from high waves in the coastal region.