Bio-based and biodegradable materials have the potential to replace traditional petroleum-based plastics across a range of products and contribute to a more circular economy. However, the uptake of these materials will not succeed unless consumers, manufacturers, and regulators are convinced of their efficacy. Investigating performance and safety concerns put forward by academic and non-academic communities, this paper assesses whether these concerns are being adequately addressed by current policy and regulation. In addition, measures to overcome significant concerns are developed through a series of stakeholder engagement events, informed by the Prospex-CQI-and STIR methodology. Discussions across the stakeholder engagement events have highlighted several concerns that create barriers to market up-take of bio-based and biodegradable plastic products, including the continued confusion regarding terminology and resultant communication, difficulties in navigating the plethora of documents related to safety, the appropriateness of safety documents when applied to new products, and the overall suitability and sustainability of such materials as an alternative to traditional plastics. To overcome these concerns, a series of recommendations for research, policy, and practice are made with respect to the following key areas of concern: regulation and legislative instruments, material quality and performance, market penetration and availability, waste management infrastructure, sourcing and supply chain, communication and information provision, and material health and safety.