The primary objective of this research is to investigate the impact of increased aquaculture output on coastal tourism and blue growth in European Union developed countries (EU13) and European Union developing countries (EU14) from 1990 to 2023. Key findings were derived through the application of resilient least squares (RLS), two‐stage least squares (2SLS), and ordinary least squares (OLS) estimators, effectively addressing endogeneity concerns. The exact magnitudes of these results show that, in EU14 developed countries, the increase of aquaculture output seriously jeopardizes the sustainability of coastal tourism more so than in EU13 developing countries. In contrast, EU14 developed countries find that variables like as economic growth and institutional quality have a greater impact on improving coastal sustainable development than do EU13 countries. Moreover, the data shows that, in comparison to EU14 developed countries, the aquaculture sector in EU13 developing countries uses more fossil fuels than EU14 developed countries, which is the main driver of carbon dioxide emissions in coastal tourist areas. In light of these findings, the study recommends that policymakers give policies targeted at enhancing productivity and encouraging the environmentally friendly growth of aquaculture production top priority, particularly in the EU14 developed countries that have significant negative effects on the sustainable development of coastal tourism.