This review discusses the molecular design of polyesters to enhance their circularity through chemical recycling, biodegradation, and mechanical recycling. Polyesters, with their reversible ester bonds, are already well-suited for circularity, as PET is the most recycled plastic, and aliphatic polyesters are biodegradable under favorable conditions. However, further tailoring is needed to enable chemical recycling under greener conditions and/or rapid biodegradation under less favorable environmental conditions. The review explores molecular design strategies to enhance circularity, including the incorporation of more easily hydrolyzable ester bonds, dynamic bonds, and degradation-catalyzing functional groups. It also reviews the use of polyester circularity to design replacement materials for current volume plastics and the embedding of green catalysts, such as enzymes, in biodegradable polyester matrices to facilitate degradation. The review covers various aspects of polyester design, including increasing biodegradability through more hydrolyzable ester bonds, increasing circularity through neighboring heteroatoms (nitrogen, oxygen, sulfur), and the use of double dynamic structures such as polyester-imines, polyester-disulfides, and polyester-acetals. It also discusses additives that catalyze polyester degradation, such as chemical and biological catalysts, and the development of polyethylene-like polyesters as more circular alternatives to polyethylene. The review highlights the importance of tailoring polyester design to specific end-of-life scenarios, considering factors such as environmental conditions, material properties, and degradation rates. It emphasizes the need for further research to understand the influence of neighboring groups on chemical recyclability, hydrolytic degradation, and biodegradation of polyesters, as well as the potential of linear polyesters in this context. The review concludes with an outlook on future research directions and the potential of polyester-based materials in achieving a more sustainable and circular economy.This review discusses the molecular design of polyesters to enhance their circularity through chemical recycling, biodegradation, and mechanical recycling. Polyesters, with their reversible ester bonds, are already well-suited for circularity, as PET is the most recycled plastic, and aliphatic polyesters are biodegradable under favorable conditions. However, further tailoring is needed to enable chemical recycling under greener conditions and/or rapid biodegradation under less favorable environmental conditions. The review explores molecular design strategies to enhance circularity, including the incorporation of more easily hydrolyzable ester bonds, dynamic bonds, and degradation-catalyzing functional groups. It also reviews the use of polyester circularity to design replacement materials for current volume plastics and the embedding of green catalysts, such as enzymes, in biodegradable polyester matrices to facilitate degradation. The review covers various aspects of polyester design, including increasing biodegradability through more hydrolyzable ester bonds, increasing circularity through neighboring heteroatoms (nitrogen, oxygen, sulfur), and the use of double dynamic structures such as polyester-imines, polyester-disulfides, and polyester-acetals. It also discusses additives that catalyze polyester degradation, such as chemical and biological catalysts, and the development of polyethylene-like polyesters as more circular alternatives to polyethylene. The review highlights the importance of tailoring polyester design to specific end-of-life scenarios, considering factors such as environmental conditions, material properties, and degradation rates. It emphasizes the need for further research to understand the influence of neighboring groups on chemical recyclability, hydrolytic degradation, and biodegradation of polyesters, as well as the potential of linear polyesters in this context. The review concludes with an outlook on future research directions and the potential of polyester-based materials in achieving a more sustainable and circular economy.