Delegates attending the fourth meeting of the ad-hoc open-ended expert group on marine litter and microplastics discussed and agreed on a Chair’s Summary to inform the fifth meeting of the United Nations Environment Assembly (UNEA-5) on how best to tackle marine litter and microplastics. In their consideration of the Chair’s Summary, they engaged in robust discussions on how to reflect what seemed like an emerging convergence around the need for a new global treaty. While many supported calls for the document to signal to the Assembly that the time has come to establish an intergovernmental negotiating committee to begin talks on a new treaty, others differed. In the end, they agreed to the Chair’s summary, which was hailed as a neutral and factual document, containing a non-exhaustive list of response options to marine litter and microplastics. They annexed the summary to the report of the meeting, which will be presented to delegates at UNEA-5. This meeting concluded the AHEG’s work, with the experts having completed the mandate accorded to them by UNEA.