This study numerically investigates the performance of a Floating Oscillating Water Column (FOWC)- breakwater Hybrid System using the Computational Fluid Dynamics (CFD) solver Ansys 2021 R1: Fluent. The domain is a two-dimensional numerical wave tank (NWT) with a partially immersed FOWC. Volume of Fluid, finite volume method and RANS equations were used to model and simulate the FOWC-breakwater hybrid system. The meshing process was done by separating the NWT to three segments, with the water surface and the middle segment having a fine element size of 0.005m, which is two times finer than the outer segments. A numerical beach was added 2m from the outlet to minimize the effects of wave reflection to the devices. Firstly, the design of FOWC and numerical setup was validated. Two models, with different top opening sizes and initial conditions were used for validation. Measurements of wave elevation and horizontal velocity were recorded and compared with experimental data from a previous study. Secondly, the FOWC-breakwater hybrid system was modelled and calculated. Four gap ratios and five wave periods were used for comparison. Measurements of wave elevation at various locations of the NWT and inside the FOWC chamber were recorded. Performance coefficients, such as the reflection coefficient, wave elevation ratio and velocity ratio, were derived from the measurements.