Sloshing has many industry applications, namely in offshore engineering, aerospace, ship building, and manufacturing. Sloshing simulation is essential to better understand the sloshing pattern and consequently to improve the tank design to reduce noise levels, stresses on the structure, and optimize the baffle configurations and arrangements. Thus, the aim of this study is to determine the effects of perforated (porous) and imperforate (solid) baffles on the sloshing pressure using ANSYS FLUENT software based on Volume of Fluid (VOF) method where a rectangular tank with 25 and 60 filling ratios was considered. In the first case, an unbaffled rectangular tank with 60 filling ratio was used for the validation purpose, while in the second case, a 25 filling ratio was investigated considering two scenarios, namely a unbaffled tank and a baffled tank case with perforated and imperforate baffles. The outcomes of the results indicate that perforated baffle can significantly reduce the sloshing pressure in the tank. The validation of the results also shows a good agreement with the published experimental results. © 2022 by the authors.