Low carbon is an important way to realize a circular economy in the ocean, and achieving carbon balance in marine fisheries is an important development method for the transformation of the traditional economy of the ocean. In this study, the carbon sinks of mariculture shellfish in China and nine provinces (regions) along the Chinese coast were measured from 2013 to 2022. The results show that the carbon sinks of marine aquaculture shellfish in China from 2013 to 2022 show a slowly rising trend, with a cumulative carbon sink of 1954.32×104 t a nd a n a nnual a verage o f 1 95.43×104 t, which is equivalent to an annual emission reduction of 717.24×104 t and an average annual saving of CNY487 million yuan in emission reduction costs. In order to further enhance the quality of carbon sinks and their economic value for mariculture shellfish, in-depth research on carbon sink measurement methods, optimization of mariculture structure, acceleration of the promotion of fishery carbon trading and the promotion of the paid ecological services of carbon sinks in aquaculture fisheries, and other countermeasures and suggestions are proposed in light of the actual situation with a view to realizing the maximum ecological, economic, and social benefits of mariculture shellfish in the future.