The impacts of plastic debris on the marine environment have gained the attention of the global community. Although the plastic debris problem presents in the oceans, the failure to control land-based plastic waste is the primary cause of these marine environmental impacts. Plastics in the ocean are mainly a land policy issue, yet the regulation of marine plastic debris from land-based sources is a substantial gap within the international policy framework. Regulating different plastics at the final product level is difficult to implement. Instead, the Montreal Protocol may serve as a model to protect the global ocean common, by reducing the production of virgin material within the plastics industry and by regulating both the polymers and chemical additives as controlled substances at a global level. Similar to the Montreal Protocol, national production and consumption of this virgin content can be calculated, providing an opportunity for the introduction of phased targets to reduce and eliminate the agreed substances to be controlled. The international trade of feedstock materials that do not meet the agreed minimum standards can be restricted. The aim of such an agreement would be to encourage private investment in the collection, sorting and recycling of post-consumer material for reuse as feedstock, thereby contributing to the circular economy. The proposed model is not without its challenges, particularly when calculating costs and benefits, but is worthy of further consideration by the international community in the face of the global threats posed to the ocean by plastics.