A three-dimensional hydrostatic Reynolds averaged Navier Stokes equation model has been applied to simulate the ice-free hydrodynamics of Lake Ontario during 2006. The model is compared to field observations to assess its ability to reproduce the fundamental physical processes driving hydrodynamics. The model correctly simulates the seasonal stratification, surface seiches and internal Poincaré waves without adjustment. Scaling of inflows is required to reproduce water levels. Surface topographic and internal Kelvin waves are simulated; however, these motions are under-resolved with the 2 km horizontal grid used in this study.