Our paper provides a quantification of plastic pollution in the Mediterranean region and several policy scenario projections based on OECD (Organisation for Economic Co-operation and Development) data toward 2100. We estimate a 4-fold increase in Mediterranean marine plastic stock by 2060 and that the implementation of terrestrial plastic cleanup can significantly help to reduce plastic pollution transfer from land to sea. Our results provide insight for policymakers, which is needed at the regional scale in the context of the UNEP (United Nations Environment Programme) plastic treaty.