Japan’s government said on July 25, 2026, that an examination of rare earth-rich mud collected from the deep seabed off a remote Pacific island earlier in 2026 went on to reveal that medium and heavy rare earth elements represented about 54% of the entire rare earth content.

But it did not reveal the magnitude of the material or the deposits, saying data was inadequate, given the short duration and geographic extent of the sampling.

In February 2026, Chikyu, the Japanese scientific drilling vessel, finished a month-long mission close to Minamitori Island, some 1,900 km southeast of Tokyo, in the first major effort to continually extract rare-earth-bearing seabed mud from a depth of roughly 6 km, equivalent to 4 miles.

The project comes as Japan looks for ways to diversify its critical mineral supply as Chinese export controls get stricter on heavy rare earths and associated magnets, key materials for the defence and automotive sectors.

Some 50 metric tonnes of mud was recovered that comprised of medium and heavy rare earth elements. The Cabinet Office’s national platform for cutting-edge ocean development found yttrium, which is used in aerospace and energy as well as semiconductor applications, gadolinium, utilized in magnetic resonance imaging along with various other high-tech applications, and dysprosium, used in highly efficient magnets when it comes to electric vehicles.

Japan plans to conduct a large-scale, month-long mining test in the same waters starting in February 2027, with the goal of digging up 350 tonnes of mud a day. The material will be dewatered at Minamitori Island and refined on the mainland to evaluate separation and refining as well as smelting technologies.

The trial is anticipated to test the viability of producing rare earth materials domestically, stated the project manager at the Japan Agency for Marine-Earth Science and Technology, which manages the Chikyu, Kazushige Kikuchi. A full evaluation of possibilities for industrialization is expected by March 2028.

In April 2025, Beijing enacted export controls on certain heavy rare earths and associated magnets and, in January 2026 and twice more the next month, increased controls on exports to Japan, focusing on large conglomerates.