The Risks of U.S. Deep-Sea Mining

As demand for critical minerals surges amid fears of overreliance on Chinese supplies, the United States has begun taking steps to secure access to the vast stores of minerals on the seabed. With international negotiations on seabed mining under the International Seabed Authority (ISA) stalled, Washington’s push to fast-track deep-sea mining under U.S. law has found support among private firms eager to begin mining. But if Washington isn’t careful, its dive into deep-sea mining risks undermining the UN Convention on the Law of the Sea (UNCLOS) and creating opportunities for China and others to bend, break, and remake the rules of the sea to their benefit—at the expense of international peace and security.

The ISA, created by Part XI of UNCLOS and a 1994 implementing agreement to regulate seabed mineral-related activities in international waters, concluded its thirtieth annual session in Kingston, Jamaica, on July 25 without much to show for it. Despite mounting pressure to finalize a mining code that would allow commercial extraction, the ISA Council again failed to reach consensus, delaying potential adoption to 2026 at the earliest. The delays stem not just from bureaucratic inertia but also from principled opposition: 38 countries have declared support for a moratorium on seabed mining pending further study of the environmental consequences.

While the rest of the world debates, the Trump administration is taking steps toward mining on the high seas under the Deep Seabed Hard Mineral Resources Act. Passed in 1980, before UNCLOS negotiations had concluded, the act has been unused since 1984, when the United States issued four exploration licenses in the Clarion-Clipperton Zone, a mineral-rich high-seas area in the Pacific.

Gridlock at the ISA has private industry getting on board with Washington. Days after President Donald Trump signed the executive order Unleashing America’s Offshore Critical Minerals and Resources in April, Canadian firm The Metals Company (TMC) applied under U.S. law for two exploration licenses and the world’s first commercial recovery permit in the Clarion-Clipperton Zone. TMC’s turn toward the United States comes after years of operation under the ISA as the industry partner of license-holders Nauru and Tonga, including a successful mining trial in the Clarion-Clipperton Zone in 2022. In June, Korea Zinc, a global leader in nonferrous metals refining, acquired a five percent stake in TMC and announced its intention to codevelop mineral processing capacity in the United States. And in July, Lockheed Martin, holder of the two remaining 1984 U.S. license areas, stated it was in talks with several mining companies to begin commercial extraction.

The Problem

But however the Trump administration goes about it, U.S. unilateral mining on the high seas poses grave risks.

The extraction of seabed minerals in international waters solely under the authority of U.S. law would run counter to UNCLOS and plunge its high seas mining regime into crisis. Member-states eager to mine would have little incentive to wait for ISA approval if Washington were to demonstrate that it could mine without it. With the ISA sidelined and no clear way for states to claim exclusive access to high-seas areas, disputes over who should be allowed to mine where would proliferate.

Such a breakdown would then lead to more important second-order consequences: It would weaken the stabilizing power of both international law and the United States over maritime issues, leaving the rules-based order more vulnerable to advances by China.

Both UNCLOS and the U.S. role in championing it have been critical in areas like the South China Sea, where China’s expansive nine-dash line claim serves as the basis for grey zone tactics aiming to deny other littoral states access to maritime resources and U.S.-allied nations freedom of navigation and overflight. Among Southeast Asian claimants, the supremacy of UNCLOS remains one of the few points of consensus that has kept Beijing from dividing and conquering in negotiations on a Code of Conduct for the South China Sea.

Proceeding with seabed mining on the high seas in clear contravention of UNCLOS, however, would shatter this dynamic. U.S. calls for China to abide by UNCLOS Part V would carry no weight if Washington were flagrantly violating UNCLOS Part XI. And attempts by others to hold China accountable would lose their bite if Washington joined Beijing in defying UNCLOS to pursue its own interests. Sooner or later—when the right leader came to power in maritime Southeast Asia—it would be much easier for them to strike a deal with Beijing in the South China Sea that would all but kill the possibility of a rules-based maritime order.

The Alternatives

This scenario is far from inevitable, and the lengthy timelines before mining operations are liable to begin leave time for Washington to consider less destabilizing pathways toward seabed mining.

The United States should prioritize exploring and recovering critical minerals within its own continental shelf. The Department of the Interior’s Bureau of Ocean Energy Management has several ongoing programs related to the exploration of these areas for critical minerals, whose exploitation rights belong solely to the United States under UNCLOS. These efforts should be supercharged, as recovering minerals within its own maritime entitlements is the best option for the United States to both comply with international law and secure resiliency of supply.

Recently announced cooperation between the United States and the Cook Islands on seabed mining within the Cook Islands’ EEZ has similar benefits in that it avoids implicating the ISA. But given that the Cook Islands is also exploring mining cooperation with China, it remains to be seen just how productive or durable the U.S. agreement will be.

Mining on the high seas is more fraught. If Washington bypasses the ISA to begin mining, it will violate a core principle of UNCLOS by exploiting the “common heritage of mankind” unilaterally. But if the Trump administration is determined to proceed along this path, it may be less destabilizing if it limits operations to the 1984 license areas held by Lockheed Martin. These licenses were issued before many states joined UNCLOS and before the 1994 amendment finalized its seabed mining regime, which may offer some space for states that would prefer to avoid a crisis to tolerate Washington’s activities as a one-time exception.

Worryingly, however, it is the worst option that appears to be closest to becoming a reality: The administration may be moving to license mining in an area already licensed by the ISA. This seems to be precisely what TMC has in mind, as it has already negotiated a deal with its ISA sponsor, Nauru, offering up to $515 million in payments if mining is approved under the U.S. pathway. A crisis at the ISA would be inevitable if the United States were to assume control of an area it had directly licensed.

Seabed minerals have the potential to play a critical role in establishing resilient rare earth supply chains. But their pursuit should not come at the cost of damaging the rules-based maritime order that the United States has worked so hard to defend. Washington should consider its options and try its utmost to avoid undermining international law on its path toward seabed mining.

Harrison Prétat is deputy director and fellow for the Asia Maritime Transparency Initiative at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Monica Sato is a research associate for the Asia Maritime Transparency Initiative at CSIS.