China mapping ocean floors for potential submarine warfare against US
What's the story
China is conducting extensive undersea mapping and monitoring operations across the Pacific, Indian, and Arctic oceans. The aim is to gather detailed knowledge of marine conditions that naval experts say could be crucial for submarine warfare against the United States and its allies, Reuters reported. A key player in this operation is the Dong Fang Hong 3, a research vessel operated by Ocean University of China.
Mapping mission
Vessel's activity in strategic waters
The Dong Fang Hong 3 was active in areas near Taiwan and Guam, as well as strategic parts of the Indian Ocean, from 2024 to 2025, the Reuters report added. In October 2024, it checked on powerful Chinese ocean sensors capable of identifying undersea objects near Japan and returned to the same area last May. The vessel also mapped waters between Sri Lanka and Indonesia in March 2025, covering approaches to the Malacca Strait.
Strategic initiative
Mapping efforts involve multiple research vessels
The Dong Fang Hong 3 is just one of many research vessels involved in China's ocean mapping efforts. Reuters analyzed over five years of movement by 42 research vessels using a ship-tracking platform. While some surveying covers fishing grounds and mineral prospecting contracts, it also serves military purposes, according to naval-warfare experts who reviewed the findings.
Military focus
China's focus on militarily important waters
China's seabed mapping efforts are concentrated on militarily important waters around the Philippines, Guam, Hawaii, and Wake atoll. The scale of this operation indicates China's intention to develop an expeditionary blue-water naval capability with a focus on submarine operations, said Jennifer Parker, a former Australian anti-submarine warfare officer. Parker, along with other experts, said the integration of civilian scientific research with military technology development has become a key focus under President Xi Jinping's "civil-military fusion" strategy.
Strategic concern
US aware of China's expanding surveying capabilities
Earlier this month, US Office of Naval Intelligence commander Rear Admiral Mike Brookes testified before a congressional commission that China has expanded its surveying efforts. He said this data "enables submarine navigation, concealment, and positioning of seabed sensors or weapons." He added that the "potential military intelligence collection" by Chinese research vessels "represents a strategic concern."
Global reach
China's ambition to achieve polar great power status
Ocean University and the Institute of Oceanology, both part of the Chinese Academy of Sciences, have stated that the larger network of sensors now provides China with real-time data on water conditions and subsea movements. Some naval-warfare specialists questioned that claim, citing technical limitations with real-time data communication from underwater. However, Parker believes that even delayed data is useful because it can assist China in detecting US submarine operations.