By Jeff Gilmour, 4 April 2026
A recent article published by Reuters mentions that dozens of Chinese research vessels are on a quest to map the sea floor at strategic locations of the world’s oceans.[1] As noted in the article, it will give the People’s Liberation Army (Navy) (PLAN) a detailed picture of the maritime environment in which submarine battles may take place in the future.
China is conducting an undersea mapping and monitoring program across all oceans, including the Arctic, ostensibly for climate, fishing and/or mining research. This exercise will increase its knowledge of marine conditions in these waters. In one example the author refers to Dong Fang Hong 3, a research vessel operated by the Ocean University of China, which spent 2024 and 2025 sailing back and forth in the waters near Taiwan and in strategic stretches of the Indian Ocean. The vessel also checked on a set of ocean sensors capable of identifying undersea objects near Japan.
US Navy officials say that the type of deep-sea data being collected by the ship is giving China a picture of subsea conditions. This information would be very useful if it needs to deploy submarines to hunt down those of its adversaries. Reuters has examined Chinese government and university records and analyzed five years of movements by 42 Chinese research vessels using a ship-tracking platform built by a New Zealand company. This indicates that the Chinese program is significant and widespread.
In recent testimony to a congressional commission, and as quoted in the article published by Reuters, Rear Admiral (USN) Mike Brookes, the commander of the US Office of Naval Intelligence, said China had dramatically expanded its surveying efforts, providing data that “enables submarine navigation, concealment and positioning of seabed sensors or weapons.” He also added that “potential military intelligence collection” by Chinese research vessels “represents a strategic concern.”
[1] Reuters, P. McKenzie, “China is mapping the ocean floor as it prepares for submarine warfare with the US”, March 23, 2026.
Image: A photo of the Dong Fang Hong 3 research vessel. Credit: Ocean University of China
