This briefing considers the environmental fate and impact, feasibility of use, and potential drawbacks associated with bioplastics, bio-based, biodegradable, oxo-(bio)degradable and compostable plastics, which are often referred to as ‘alternative plastics’ and which are increasingly being put forward as solutions to the problem of marine plastic pollution. In developing solutions it is important to consider ways in which alternative plastics may perpetuate existing environmental threats and further burden already struggling waste management infrastructure, as well as reflecting on the compatibility of their use with circular economy principles. Hence, more attention must be paid to the most suitable materials for specific applications, and that there is an overriding need to reform single and wasteful resource use.