Growing evidence of the prevalence of plastics in the oceanic environment is causing increasing concern. In this study we consider the possible impact of major changes to the supply and consumption of plastics. While we recognize that tackling the problem of plastic debris in the ocean calls for integrated solutions, our analysis contributes to filling the gap in knowledge about the effectiveness of intervention strategies. Our results find that strategies addressing plastics demand have a greater impact than those focussing on plastics supply. However, only measures aimed at plastics supply are effective in the short run. These considerations can help to inspire the prioritization of intervention strategies and to contribute to the design of integrated interventions aimed at tackling the problem of marine plastic debris through a systemic approach.