Although CFD computation can predict resistance for conventional vessels with reliable accuracy at deep water condition, its predictive capability at shallow water condition is still unclear. One of the main objective of this study is to assess the accuracy of CFD computation for this kind of configuration and attempt to identify physical phenomena poorly modeled in the simulation. Shallow water resistance and squat are predicted for two different ship models, namely the DTC container ship, and the KVLCC2 tanker. Numerical uncertainty related to grid density, turbulence model as well as near wall turbulence model treatment will be investigated. Computation at full scale is also performed for the container ship to check the scale effect in ship squat prediction.