This chapter surveys Japan’s public maritime legal framework across three parts: institutional context; key public maritime laws; and emerging challenges. The first section introduces Japan’s major shipping industry; its active role in the International Maritime Organization (member since its founding and active contributor) and ratification of global maritime conventions; and national authorities (e.g., the Ministry of Land, Infrastructure, Transport and Tourism, and the Japan Coast Guard) administering maritime law. The second section reviews key public maritime laws in areas of ship safety (e.g., SOLAS/Ship Safety Act), marine environmental protection (MARPOL and pollution prevention laws), seafarers’ labor and training (including Japan’s ratification of the Maritime Labour Convention, 2006), and port state control (through the Tokyo MOU regime). The third section discusses emerging challenges: regulatory responses to shipping decarbonization, digitalization (e.g., autonomous ships and related legal reforms), and efforts to strengthen seafarers’ rights and welfare. This study aims to provide a comprehensive reference for legal scholars, policymakers, and maritime professionals engaged in maritime governance.