This study aims to develop an efficient and accurate analytical-numerical model to analyze full interaction between seawater waves and cylindrical floating breakwaters in an infinite fluid domain of finite arbitrary water depth. Based on potential flow assumption, a semi-analytical Scaled Boundary Finite Element Method (SBFEM) in a two-dimensional vertical plane has been used to solve governing Laplace equations. The final equation in the scaled boundary coordinate system has been homogenized by locating the scaling center within each sub-domain. Hence, a diversity of particular solutions are omitted, leading to a unified solution process for radiation/different modes and wave diffraction problems. The accuracy, generality and robustness of the proposed SBFEM model have been evaluated by comparing the results of the proposed model with the reported results from the literature. By implementing the current SBFEM model, simulation results for radiation and diffraction problems are highly accurate compared to the result of other solutions.