Numerical simulation of transom stern flow has proven to be an interesting topic, but a complicated task in the hydrodynamic field of research. In this paper, a three-dimensional numerical simulation is presented using Ansys-CFX to survey the free surface flow, downstream of the transom stern. To this end, finite volume method coupled with volume of fluid is utilised and k-ϵ turbulent model is applied. The numerical solutions are validated by comparing the findings against the results of empirical formula available in the literature. In order to conduct a parametric study, four different Froude numbers, four trim angles, and two deadrise angles are considered and the effect of each of these parameters is studied.