China Owns the Land. Can the Allies Own the Deep?

The US and Japan are partnering to mine rare-earth-rich Pacific seabed deposits, aiming to cut dependence on China

31 Mar 2026

The United States and Japan have signed a memorandum of cooperation on deep-sea mining, formally aligning two major economies in the race to secure critical minerals from the Pacific Ocean floor. Agreed at a leaders' summit in Washington in March 2026, the deal establishes a joint working group to share research on seabed mineral extraction, focused on rare-earth-rich deposits near Japan's Minamitorishima Island, around 1,200 miles southeast of Tokyo.

Japan's deep-sea drilling vessel Chikyu recently retrieved sediment from nearly 6,000 metres below the Pacific surface, a technical milestone for deposits previously considered commercially unviable at scale. The abyssal muds are rich in neodymium, dysprosium, and terbium, rare earth elements central to electric vehicle motors, wind turbines, and precision defence systems.

The strategic logic is straightforward. China controls the overwhelming majority of global rare earth refining capacity. Both governments have concluded that the ocean floor represents one of the most credible routes to supply diversification available to them.

The memorandum was circulated at the International Seabed Authority's March 2026 session, where member nations again failed to finalise a global mining code after a decade of negotiations. The US operates outside that framework, having revised its NOAA permitting rules in January 2026 to allow consolidated exploration and commercial recovery applications in a single step. Japan's formal cooperation represents the most significant allied endorsement of that approach to date.

Governance tensions persist. Japan is a signatory to the UN Convention on the Law of the Sea, and legal experts note that operational cooperation in international waters could create complications for Tokyo under existing treaty obligations. Around 40 nations have called for a moratorium on deep-sea mining pending clearer environmental standards, and scientists warn of risks to fragile seabed ecosystems.

Whether the alliance can advance extraction at commercial scale without triggering a wider legal dispute with UNCLOS signatories remains the central unresolved question. The agreement places seabed minerals at the heart of allied industrial strategy; how international governance responds may determine whether that strategy holds.