Collimators are beamline components used to define the beam aperture and intercept halo particles in order to protect downstream equipment and reduce uncontrolled losses. In this project, electromagnetic wakefields in an existing beam collimator geometry will be studied using CST Studio Suite. The geometry is already available and will be imported into CST for numerical wakefield simulations. The focus is on extracting and analyzing key wakefield quantities such as longitudinal and transverse impedances extract loss and kick factors, shunt impedances, quality factors and resonance frequencies. The simulation outputs will be post-processed using the provided post-processing software in MATLAB.