Meeting the ambitious GHG emission reduction target necessitates the continual innovation and implementation of both operational and technical solutions to optimize vessel performances. One practical approach is to optimize a vessel’s static trim, which can impact its resistance and propulsive power. The standard approach for conducting hull trim optimization studies is typically based on model-scale tests or simulations. However, there may be discrepancies in the estimated savings between the scaled-up and full-scale performances due to scale effect distortion, which may emphasize performance benefits or penalties calculated in model scale. To examine these possible scale effects, this paper compares the results from full scale Computational Fluid Dynamic (CFD) and model scale simulations. The study considers a 237m Container Ro (Con-Ro) vessel and analyses the full-scale performances at a specific trimmed load condition for different speeds. Full scale CFD simulations were validated against available towing tank data.