<p>Addressing the contradiction between economic growth and carbon balance in rapidly urbanizing regions, this study constructed a dynamic annual carbon balance database at the municipal level for the Yangtze River Delta region (YRD). It employed a carbon balance zoning system quantified using carbon economic contribution coefficients (CECC) and carbon ecological support coefficients (CESC), and utilized an improved Tapio model to analyze the decoupling relationship between economic development and carbon emissions (CE). The results showed that: (1) From 2005 to 2022, the carbon sink (CS) volume in the YRD increased from 2827.80 × 10⁴ t to 3908.88 × 10⁴ t, with ecological restoration projects making the most significant contribution to this increase. (2) Regional CE are primarily driven by energy consumption, with significant spatial variations. (3) The evolution of carbon balance zones reveals that an optimized pattern dominated by “low-carbon maintenance zones” and “CS development zones” has formed across the region, with continuous improvements in the ecological environment. (4) The YRD as a whole is in a state of “weak decoupling” between economic growth and CE, having preliminarily achieved a virtuous cycle between economic transformation and low-carbon development. Furthermore, based on the research findings, this study proposes policy recommendations to promote green transformation and low-carbon development in the YRD, which can provide a basis for policy-making regarding sustainable development and carbon reduction in similar urbanized regions.</p>