Stepped labyrinth spillways are effective hydraulic structures that significantly enhance energy dissipation due to their rough surfaces. These spillways are engineered to discharge excess water. Currently, the accessibility of commercial computational fluid dynamics (CFD) programs and high-performance computers allows us to estimate various hydraulic parameters of flow. The turbulence model and a three-dimensional CFD can be used to examine and comprehend the spillway flow’s unique complexity and speed fluctuations. This study used the commercial programme ANSYS FLUENT version 22 to quantitatively evaluate the water flow characteristics across a labyrinth stepped spillway. It attempted to validate the model’s correctness and dependability while simulating the flow over these types of hydraulic structures, through a comparison of the numerical model’s outcome with previous experimental data. The 3D incompressible flows using the RNG k-ε turbulence model and the volume of fluid method were employed together as one single structure for model simulation. All hydraulic characteristics from experimental results, such as the water surface profile, hydraulic head, and velocity, were compared with the numerically obtained results. The comparison process aimed to validate the CFD models. Statistical indices indicated acceptable agreement between the numerical and experimental results. Regarding velocity over the steps, the measured absolute error varied from 0.3% to 7.25%. The numerical results showed that the breadth of the labyrinth cycle and the water depth on the steps determine the local direction of flow. Furthermore, it was noted that the impingement angle of the water velocity vectors has an appreciable influence on the directions of streamlines and contours.