The sloshing phenomena is a critical engineering problem encountered by designers in the oil and gas industry and causes damages to the tank walls. Thus, in this study, the effects of sloshing in a spherical tank with double-side curved baffle was investigate using numerical simulation. Two cases were considered in this simulation. A spherical tank without curved baffle was modelled in the first case, then, in the second case, a double-side curved baffle was introduced. The simulation was conducted considering three filling levels of 30, 50, and 75 using ANSYS CFX software. The outcome of the study shows that introducing double-side curved baffle has significantly reduced the sloshing force, the sloshing pressure, and the fluid velocity in the tank. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.