Abstract. The simulation of free surface flow is a computationally demanding task. Real life simulations require often the treatment of unstructured grids to capture the complex geometries and the use of parallel supercomputers for the efficient solution. For that aim, we have developed an efficient parallel free surface flow solver based on a full tetrahedral discretization. An implicit stabilized finite element method is used for solving the unsteady incompressible two-phase flow in three-dimensions. A pressure stabilized Petrov Galerkin technique is used to avoid spurious pressure modes, while an upwind finite volume discretization is used to discretize the advective fluxes in a stable manner. The interface between the fluid phases is captured with the level set method implemented with a quadrature-free discontinuous Galerkin method. The parallel implementation is based on the MPI message-passing standard and is fully portable. We show the effectiveness of the method in the simulation of complex 3D flows, such as the flow past a cylindrical and the flow in a partially-filled tank of a car that suddenly brakes.