Sloshing is a phenomenon where the tank experiences an external oscillating motion due to the interaction of fluid with tank. The most appropriate way to prevent instability from the sloshing movement is to add baffles or anti-sloshing. This paper was conducted with the 3D simulation of sloshing roll motion on the prismatic tank with a simulation time of 28 seconds. Vertical and Horizontal baffles were used to mitigate sloshing in the prismatic tank. The ratio of baffle height and water depth is 0.7, 0.8 and 0.9. Moreover, horizontal baffle position is 0.1, 0.2, 0.3, and 0.4 respectively, with the tank filling water ratio is 25%. The numerical study was carried out using meshfree CFD, i.e., Smoothed Particle Hydrodynamics. In addition, advanced post-processing was conducted with Blender. The aims of this study were found out the effective baffle configuration ​​to reduce sloshing using vertical and horizontal in the prismatic tank. The results showed the most effective baffle variation for roll motion is 0.9 for vertical baffle and a horizontal baffle height is 0.1 from the water surface. It showed baffles effectively reduces dynamic pressure, hydrodynamic force and free surface deformation