China is carrying out a large-scale effort to map the ocean floor across the Pacific, Indian and Arctic oceans, in a move analysts say is aimed at strengthening its submarine warfare capabilities against the United States and its allies.
The operation involves dozens of research vessels and extensive networks of underwater sensors gathering detailed data on seabed terrain and ocean conditions. While officially described as scientific research, experts say the information has clear military value.
Chinese vessels, including the Dong Fang Hong 3, have conducted repeated missions near strategically sensitive areas such as Taiwan, Guam, Japan and key shipping routes like the Malacca Strait.
The data being collected includes seabed topography, water temperature, salinity and ocean currents. This information is critical for submarine operations, allowing vessels to navigate more safely, remain hidden and detect enemy submarines more effectively.
Analysts say the scale of the effort signals China’s ambition to build a “blue-water” navy capable of operating far from its shores, with a strong focus on undersea dominance.
The program is part of China’s broader “civil-military fusion” strategy, where civilian research institutions work closely with the military. Data gathered for scientific purposes can be repurposed to support naval operations and intelligence gathering.
U.S. officials view the campaign as a growing strategic concern. The expanding database of underwater conditions could erode a long-standing U.S. advantage in submarine warfare by improving China’s ability to track and counter rival submarines.
China has also deployed sensor networks in key waterways, aiming to create what some researchers describe as a “transparent ocean” — a system capable of monitoring underwater activity in real time or near real time.
The mapping extends to regions near major U.S. military hubs, including Hawaii and Guam, as well as routes critical for global trade and energy transport.
The effort reflects a broader shift in global military competition, where control of the underwater domain is becoming increasingly central to strategic advantage.
