Oxygen isotope analyses were carried out on the topshell Osilinus turbinatus from archaeological sites with the aim to investigate the temporal exploitation patterns by Mesolithic groups inhabiting coastal caves in SW Italy. In order to assess the present day O. turbinatus intra-annual δ18O variability, living specimens were collected monthly at Marina di Camerota (SW Italian peninsula). Their shell-edges were analysed and the seasonal results were compared with archaeozoological material. Our findings show that Mesolithic O. turbinatus exploitation was carried out almost exclusively during the colder and intermediary seasons (e.g. autumn, winter, spring), with very sporadic harvesting during the warmer seasons. Results suggest a possible regional exploitation pattern of O. turbinatus by Mesolithic groups inhabiting this region.