Optimizing the design of monopile foundations is crucial for cost competitiveness in offshore wind farms. This requires considering regional climate and soil conditions. The p-y method is used for soil–structure interaction instead of extensive numerical simulations. However, the conventional Winkler beam method, recommended in offshore design codes, is losing favor due to its calibration based on oil and gas platform foundations. Therefore, new methods are proposed for calibrating the soil reaction curves. However, there are uncertainties associated with the newly developed soil reaction curves also which are not incorporated in the study. The research uncertainties considered in the present study are the scouring effect on the soil surface and how this phenomenon can affect the serviceability limit of monopile foundations. The presented methodology assesses the reliability of the serviceability limit state of the monopile foundation through probabilistic evaluation. The variability-scour-related parameters are incorporated in the random finite element model. A series of three-dimensional random finite element simulations are performed using PLAXIS 3D, in which the random-scour-related parameters are obtained through Monte Carlo simulations. After the reliability assessment, a comparative study is shown to capture the deviation in serviceability limit where the scouring effect is not considered.