This research aims to study the comparative advantage of seafood exported from Vietnam to the Japanese market. During the research process, the authors analyzed the comparative advantage of Vietnamese seafood exported to the Japanese market through comparative advantage indexes including RCA, and regional orientation RO index for the period 2011-2020. Through research, groups of goods with codes HS0304, HS0306, and HS1605 have a high comparative advantage. Other commodity groups in Vietnam are gradually losing their comparative advantage. In addition, the authors chose China and Norway to compare, which are two major exporters of seafood to Japan. From the research results, the authors propose solutions to improve comparative advantage for groups of seafood with high comparative advantage and those with low or no comparative advantage and develop the supply chain of seafood for export.