Catastrophic tsunami events, such as the 2004 Indian Ocean and 2011 Tohoku Tsunamis, have highlighted the vulnerability of coastal infrastructure and the urgent need for effective mitigation strategies. Among various countermeasures, water-filled canals have been proposed as an effective approach for reducing tsunami-induced forces on structures located near affected shorelines. Although a limited number of field observations, experimental studies, and numerical simulations have demonstrated the potential of canals to dissipate tsunami bore energy, further research is needed to understand better the detailed interactions between tsunami bores and water-filled canals. This study presents the results of a series of numerical simulations calibrated and validated with experimental results to evaluate the effectiveness of rectangular water-filled canals in mitigating the horizontal force exerted by a tsunami-like bore on a vertical column located behind the canal. The simulations were conducted at a prototype scale using FLOW-3D, a well-known CFD tool known for its ability to model complex free-surface flows and fluid-structure interactions. A dam-break method was used to generate a tsunami-like bore that propagated along a dry horizontal bed, crossed over a water-filled canal, and impacted a square column. The analysis focused on bore hydrodynamics, the time history of the force, and bore interactions with the canal and column. Results show that canal geometry plays a critical role in reducing bore front velocity and the resulting impact force on the column. For a canal with a depth of 4.5 m and width of 40 m, the maximum horizontal force exerted onto the column was reduced by up to 40%. These findings demonstrate that well-designed water-filled canals have the potential to serve as effective tsunami mitigation countermeasures and that proper design of such a canal geometry is essential for optimizing its performance.