Plastic waste has become a major contributor to global environmental pollution. Some of the environmental impacts of plastic waste include littering, the formation of plastic debris in oceans and the contamination of freshwater and terrestrial habitats. Policymakers face great challenges in mitigating plastic waste. Indonesia is considered the second largest contributor of plastic waste in the world. However, existing policies have not addressed this issue. Policies, such as bans on single-use plastic bags and fees on plastic bags, have recently been implemented in some pilot cities, but the results remain unclear. Thus, this study proposes feasible policies to mitigate plastic waste in Indonesia using system dynamics. Specifically, this study seeks to develop a dynamic model of plastic waste mitigation and to propose a policy scenario for plastic waste mitigation. The proposed policies consist of a plastic bag ban, a plastic bag fee, a recycling centre and extended producer responsibility (EPR). The analysis demonstrates that an effective mixed policy instrument for reducing plastic waste depends on the plastic waste type. Regarding plastic bottles, the effective mixed policy is a combination of a recycling centre and EPR. For plastic bags, the effective mixed policies include the following combinations: a plastic bag fee and plastic bag ban, a plastic bag fee and recycling centre and a plastic bag ban and recycling centre.