Employing Porter's diamond model, we investigate the determinants of competitive advantage in the global seafood export market. We use annual data spanning 2000-2017, which were pooled from five countries with similar export characteristics, that is, China, Japan, South Korea, Spain, and Thailand. Among several significant factors, we find that improving seafood production efficiency is far more important than natural resource amounts in determining seafood exports' competitiveness. We also find that, along with the inflow of labor into the fishery industry, product-quality improvement through domestic consumption market growth and environmental improvement in related industries are crucial factors for competitiveness. Finally, the government's role is pivotal in the competitiveness of a country's seafood export industry. Policymakers need to exert efforts toward diversifying trade partners and avoiding regulation violations that may lead the country to be designated as, for example, an illegal, unreported, or unregulated fishing country.