China’s ratification of the United Nations Convention on the Law of the Sea (UNCLOS) not only helped Beijing to adapt to contemporary global ocean governance, but also reinforced the importance for China to develop a maritime strategy to safeguard its maritime rights and interests. For instance despite China’s rejection of the 2016 arbitral tribunal ruling of the Philippines’ case against China in the case of the South China Sea, it still refers to UNCLOS (rather than simply dismisses it) to explain its decision. It can be expected that UNCLOS can be a tool of political contestation in the great power competition between Beijing and Washington.