AbstractDegradable polyester elastomers are highly desirable for biomedical applications. Here, highly transparent and degradable aliphatic polyester elastomers were prepared using the ring‐opening copolymerization (ROCP) of commercial monomers, followed by a photo‐crosslinking process. A series of the semi‐crystalline copolyester (PMBL‐co‐PBL‐co‐PCL) precursors with different molecular weights and pendent vinyl contents were synthesized by one‐pot ROCP of α‐methylene‐γ‐butyrolactone (MBL), ε‐caprolactone (ε‐CL) and γ‐butyrolactone (γ‐BL). Then, UV irradiation was applied to photo‐crosslink the precursors to obtain several elastomers. The obtained aliphatic polyester elastomers (CPEs) displayed excellent mechanical properties with high tensile strength (11.3 MPa), high elongation at break (1300%) and high elastic recovery (about 99% after 10 hysteresis cycles). In addition, the elastomer showed much better stability than uncrosslinked (co)polyesters, but maintained degradability in the basic aqueous solution, with ~30% of the mass loss in 1 M NaOH solution after 30 days. Through efficient ROCP, we demonstrated a strategy to prepare degradable CPEs bearing high strength, good elasticity, excellent resilience and degradation capability, which can serve as sustainable elastomers for various applications.