<p>To investigate the coordinated development mechanism and dynamic relationship between the marine economy and marine environment in China’s coastal areas, this research focuses on 11 provincial-level administrative regions situated along China’s coastal areas as its study subjects. Based on panel data from 2013 to 2022, the coupling coordination degree model and Tapio decoupling model are used for empirical analysis. The research establishes an economic system evaluation framework centered on the robustness, composition, and technological sophistication of the marine economy, while concurrently developing an environmental system evaluation system that takes into account resource availability, environmental quality, and pressure levels. The entropy weight approach is employed to ascertain the weights of indicators, and data standardization is accomplished through the range method. Grounded in this, the coupling coordination degree model is utilized to measure the coordinated development level of the two systems, and the Tapio decoupling model is employed to analyze the dynamic correlation between marine economic growth and environmental pressure. The findings reveal that the average coupling coordination degree increases from 0.5890 to 0.6210, and the coordination type shifts from mainly imbalance to dominated coordination. SD and GD maintain a high level of coordination, with significant regional differences. The decoupling status shifts from a negative decoupling of global expansion in 2013 to a decoupling of global recession in 2022, reflecting the development model’s shift towards green transformation. The research reveals that policy regulation and technological innovation are key drivers for coordinated development, offering a scientific foundation for refining the strategy aimed at the coordinated advancement of the marine economy and environment in coastal regions.</p>