The question whether it is time for marine morphodynamic models to take into account the 3-D nature of water and sediment motion is discussed starting from practical demand and the state-of-the-art in basic knowledge and model development. This leads to the observation that there is a clear practical demand, and that suitable software environments and some 3-D model components exist, but that the basic knowledge on 3-D morphodynamic processes and the necessary know-how for utilizing these models are still insufficient. Hence it is concluded that there is an urgent need for modelling-oriented research on 3-D marine morphodynamics, but that it is too early to develop modelling facilities for practical application.