China’s primary cultural identity tends to be associated with land-oriented, agrarian civilization, despite its lengthy coastline and history of maritime activities. But for the 21st century, as the Chinese central authority has developed a comprehensive national ocean strategy, it has purposefully crafted an identity of China as a maritime great power. Chinese agencies refer to this work as promoting ocean soft power (提升海洋强国软实力)via ocean consciousness propaganda (海洋意识宣传), ocean education (海洋教育) and ocean culture (海洋文化). Based on analysis of Chinese-language sources back to the 1980s, this article examines the origins, planning and implementation of China's state-constructed maritime identity. The article explains the roots of ocean culture and traces how an ocean consciousness campaign expanded from the military to the population in the 1990s, the systemisation of which has culminated in a five-year plan and a National Ocean Consciousness Index. Practical implementation unfolds in the recasting of fifteenth-century navigator Zheng He as a cultural icon; the state's appropriation of Mazu mythology; and use by local governments to foster economic growth. This effort is primarily domestically oriented but has significant international implications. The narrative produced is likely to shape China’s role in the global commons, on issues from marine environment and natural resources to polar affairs, boundary disputes and maritime security.