Plastic pollution is a diffuse, cumulative and value chain-generated environmental problem that remains insufficiently addressed by existing product, waste and market regulations. This article examines the potential of the EU Corporate Sustainability Due Diligence Directive (CSDDD) to function as a horizontal governance mechanism capable of embedding plastics-related risk management within corporate decision-making. Using a doctrinal and governance-oriented analytical framework, the article assesses whether plastic pollution qualifies as an “adverse environmental impact” under the Directive, how its risk-based obligations may apply across upstream and downstream stages of plastics value chains, and how its enforcement architecture shapes corporate accountability. The analysis demonstrates that, although the CSDDD does not directly regulate plastics, it can procedurally operationalise existing EU plastics and circular economy objectives by integrating environmental risk management into corporate governance systems. At the same time, its effectiveness is constrained by structural limitations, including the exclusion of post-consumer stages, challenges of causation in diffuse pollution contexts and variations in enforcement across Member States. The article contributes a systems-oriented assessment of regulatory coherence at the intersection of plastics governance and corporate due diligence, while critically evaluating the limits of procedural regulatory approaches in addressing systemic environmental harm.