China is rapidly expanding its deep-sea research and mapping efforts across key global waters, raising concerns that these activities may support future undersea conflict.
This month, Reuters and CNN reported that China is expanding a vast deep-sea research and mapping effort across the Pacific, Indian and Arctic oceans, combining resource exploration with strategic data collection that analysts say could support future submarine warfare against the US and its allies.
Dozens of state-linked Chinese research vessels have spent years surveying seabeds, deploying sensors, and mapping underwater terrain in areas near Taiwan, Guam, the Philippines, and key maritime chokepoints, generating data on temperature, salinity, and acoustic conditions critical for submarine navigation and detection, the reports said.
CNN shows at least eight Chinese vessels conducting deep-sea mining exploration missions over five years, often exhibiting patterns — such as disabling tracking systems and operating beyond licensed zones — that experts say suggest dual-use, military-civilian objectives aligned with China’s “military-civil fusion (MCF)” strategy.
China holds five of 31 exploration contracts issued by the International Seabed Authority (ISA) and is positioning itself as a leader in a nascent industry expected to supply critical minerals, even as scientists warn of severe environmental risks.
The scale and location of China’s activities indicate a broader push to enhance maritime reach, secure resources, and prepare the undersea battlespace. It also reflects a broader strategy that leverages seabed exploration to advance undersea military capabilities while securing long-term economic and technological advantage.
These efforts suggest China is not merely collecting data but systematically shaping the undersea environment to its operational advantage. Official US testimony suggests China is building a layered undersea surveillance and control architecture designed to contest US advantages below the surface.
US Vice Admiral Richard Seif says in a US Senate testimony that these efforts aim to build a layered undersea surveillance architecture capable of contesting US submarine freedom of maneuver, particularly through “seabed sensing and networked surveillance in key maritime approaches.”
He says this “Underwater Great Wall” integrates fixed sensors, unmanned systems, and data networks to generate persistent awareness at chokepoints and littorals, with the operational goal of reducing US submarines’ stealth advantages by leveraging detailed bathymetric knowledge. Seif adds that such networks could also interfere with seabed infrastructure, including cables and sensor nodes.
Rear Admiral Mike Brookes says in a separate testimony that China’s oceanographic and hydrographic collection supports both offensive and defensive undersea operations, including sea denial, deterrence and strikes on high-value targets.
He says environmental data—temperature, salinity, and currents—enhances sonar performance and enables persistent detection in key waterways, while seabed mapping and commercial surveys provide dual-use intelligence for navigation, concealment, and emplacement of seabed systems.
Brookes adds that such data reveals optimal transit corridors and acoustic conditions, shaping tactical advantages in the undersea battlespace. Together, these assessments point to a shift from passive data collection to active preparation for the battlespace.
Extending this logic, Andrew Erickson argues that China’s “transparent ocean” concept seeks to transform the seabed into a persistent, data-driven battlespace through military-civil fusion and large-scale integration of oceanographic data.
He says seabed platforms and deep-sea systems could enable sustained presence and pre-positioning at chokepoints, while treating the seabed as both a resource domain and a warfighting arena, including for the control or exploitation of undersea cables.
This emerging undersea capability has immediate implications for conflict scenarios, particularly in the Taiwan Strait. Jason Hsu says China’s undersea activities enable a strategy of selectively disrupting communications, with repeated cable-cutting incidents indicating detailed seabed knowledge and deliberate targeting of vulnerable links.
He says the PLA could sever key cable clusters to cut bandwidth by up to 99%, creating a “digital quarantine” that isolates Taiwan, disrupts allied coordination and amplifies psychological pressure alongside military operations.
To put that in perspective, multiple reports note that Taiwan relies almost entirely on undersea cables for internet connectivity, making the self-governing island especially vulnerable to an information blockade. This vulnerability turns seabed knowledge from a technical advantage into a strategic lever.
Beyond cutting off Taiwan from the Internet as part of a blockade, China’s deep-sea research and mapping efforts may indicate it is aiming to conduct submarine operations beyond the First Island Chain.
Brookes states China has expanded its submarine production capacity, increasing facilities for conventional submarines while shifting toward greater reliance on nuclear-powered platforms.
Extensive hydrographic and underwater mapping might be necessary to fully utilize the nearly unlimited range of nuclear propulsion, enabling missions in the Second and Third Island Chains and possibly in the Indian Ocean.
These operations could involve escorting China’s carrier strike groups into the Pacific, threatening US carriers in the region or tracking India’s nuclear ballistic missile submarines (SSBNs) in the Bay of Bengal.
However, China still faces geographical constraints, requiring passage through chokepoints such as the Miyako Strait, Bashi Channel, and Malacca Strait to reach open waters, underscoring the need for detailed mapping of alternative routes through Southeast Asian straits.
China’s push into seabed mining is less about immediate extraction than positioning for long-term control over critical mineral supply chains. Tom LaTourrette and other writers note in an April 2025 RAND report that China’s strategic focus on deep-sea mining primarily concerns critical minerals security and supply-chain leverage.
LaTourrette and others say China is “aggressively pursuing seabed mining itself,” has “more exploration contracts and influence with the International Seabed Authority (ISA) than any other nation,” and “explicitly includes seabed mining among its national strategic objectives.”
As of May 2025, the Asia Maritime Transparency Initiative (AMTI) reports that three Chinese companies — China Ocean Mineral Resources Research and Development Association (COMRA), China Minmetals Corporation, and Beijing Pioneer Hi-Tech Development Corporation — collectively hold five ISA licenses, the highest number held by any single sponsoring country.
This growing footprint is not just commercial — combined with China’s ISA engagement, it establishes early presence in a sector where rules and access are still being defined — and increasingly influenced by early movers.
Seabed mining could strengthen China’s position in critical minerals and potentially reinforce its broader leverage across rare-earth-related supply chains.
Rare earth elements are critical to modern economies because their unique properties underpin clean energy technologies, digital systems, high-tech manufacturing, medical equipment and military capabilities, making them indispensable amid rising global demand and tightening supply.
China already dominates the rare-earth sector — controlling 60% of supply and 85% of processing capacity — while the US remains heavily dependent, sourcing 71% of imports from China, a gap that seabed mining could further entrench.
China’s deep-sea research links military and economic goals, creating a new model of undersea power that combines resource control, data and battlespace preparation. As these activities expand, the boundary between commercial and military will blur, potentially allowing China to sustain persistent access in vital maritime zones.
The long-term implications are a shift from episodic naval competition to continuous, infrastructure-driven undersea contestation, reshaping deterrence, hardening supply chain dependencies and raising the risk of disruption in future crises.