Investment in coastal wetland restoration yields high returns in blue carbon and ecosystem services in China

China’s coastal wetland degradation and loss threaten critical climate mitigation and ecosystem services. While substantial restoration investments, the economic rationale for these efforts remains poorly understood. Here we address this gap through a comprehensive data synthesis of 237 coastal wetland restoration projects (2000-2020) across China, totaling US$8.87–13.8 billion in investment. This analysis provides a 30-year cost-benefit assessment for restored salt marshes, mangroves, and seagrass beds. Our study reveals considerable returns on these restoration projects, with an estimated blue carbon gain of 8.50 ± 3.76 million tons and an enhancement of ecosystem service value by US$95.9–434 billion. Benefit-cost ratios of Chinese coastal wetland restoration ranged from 7.01 to 18.8 for salt marshes, 15.5 to 47.0 for mangroves, and 16.3 to 43.7 for seagrass beds. Despite uncertainties in monetary valuation, our ecological and economic findings support integrating coastal wetland restoration into national climate strategies and coastal spatial plans. Restoring China’s salt marshes, mangroves, and seagrass beds offers economic and ecological benefits, with estimated blue carbon gains up to 12.3 million tons and the value of ecosystem services up to 434 billion US dollars, according to data from 237 coastal projects.