Résumé
Marine Protected Areas (MPAs) are a cornerstone of marine conservation efforts, with the potential to protect biodiversity and provide socioeconomic benefits. We quantified the effect of MPAs on fishing outcomes, economic activities, and material living standards in 24 coastal villages of Tanzania over two decades. We accessed original data from a study conducted in 2003 that found no effect of MPAs 3–8 years after their creation. Eighteen years later, we replicated the survey and used a Before‐After Control‐Intervention design to quantify the effect of MPAs. We found that villages near MPAs experienced a 50% higher improvement in living standards compared to those further from MPAs. This benefit is not related to higher fishing outcomes but to a diversification of economic sectors. Our findings highlight a decoupling between fish catches and economic benefits, revealing that socio‐economic outcomes can be observed for MPAs whose ecosystems’ productivity has declined.