Abstract
International cruises have drawn worldwide attention since the outbreak of coronavirus (COVID-19). This article first examines the legal issues, challenges and impact of the pandemic on large cruise ships, like the Diamond Princess, and then probes into corresponding pandemic preventive measures which port states employ. A State is obliged under the International Health Regulations 2005 (IHR) to grant foreign cruise ships free pratique, but there is an exception when public health emergencies of international concern occur. Therefore, this article argues that a port state is not obliged to allow foreign cruise ships to dock at its port at the cost of its domestic public health safety. Regarding the Diamond Princess, the Japanese government has undertaken pandemic preventive measures upon passengers on board the ship and complied with its domestic laws, including the Japanese Quarantine Act. This article further evaluates whether a port state's pandemic preventive measures concerning cruise ships are appropriate from the perspective of law. More importantly, it is necessary to consider the characteristics and specialities of international cruise ships to improve future pandemic preventive measures against large passenger ships and cruise passengers.