We present a case of a 74-year-old male with symptomatic premature ventricular complexes (PVC) localized to the proximal coronary sinus (CS). Despite initial mapping identifying the basal inferoseptal left ventricle, the closest electrogram was found within the CS, confirmed during a spontaneous PVC. Ablation at this site resulted in immediate PVC suppression, sustained at 3-month follow-up. This case underscores the utility of advanced mapping techniques, including intracardiac echocardiography and activation mapping, in identifying and successfully ablating PVCs at unusual sites such as the proximal CS.