In this paper, parametric analyses of rainfall infiltration into soil were conducted using a numerical model created with the GeoStudio software package (GEO-SLOPE International Ltd.). Rainfall infiltration is an important process in geotechnical engineering, as it affects soil moisture, pore pressures, and soil strength, and thus has a significant impact on slope stability. In this study, a numerical model was developed based on an experiment conducted at the Geotechnical Laboratory of the Faculty of Civil Engineering in Rijeka. The experiment involved a physical slope model made from uniformly graded fine sand, compacted to predefined moisture and density conditions, instrumented with various sensors to monitor hydraulic and mechanical responses, and exposed to simulated rainfall under 1g loading conditions. In the first step, the numerical model was defined with a basic set of parameters representative of the tested material, and the results of the numerical and physical models were compared in terms of measured and calculated values of volumetric water content and pore pressures in the model. Following that, parametric analyses were conducted by varying each individual parameter defining the hydraulic properties of the soil in order to analyze their impact on the model's response. The analyses indicate a significant influence of parameter changes, such as soil permeability, initial moisture content, and retention curve parameters, on the results of the numerical model.