Japan weighs nuclear submarine acquisition to counter China's maritime expansion

Reports have emerged that Japan's government is considering including a review of nuclear submarine acquisition for the Self-Defense Forces in its three key security documents, which are set to be revised this year.

The Yomiuri Shimbun reported Tuesday that if the review is explicitly written into the documents, the groundwork for related investigation and research would be laid, with a final decision on acquisition expected to follow over several years.

The proposal has gained traction from a broad consensus that Japan must do more to check China's expanding maritime reach. Japanese authorities have concluded that as China intensifies its push into the Pacific and other seas, deploying nuclear submarines — capable of remaining submerged for extended periods — is essential to countering that advance.

Nuclear submarines offer not only long-duration submersion capability but also greater speed than conventional diesel-powered vessels, allowing for more agile responses in coastal surveillance and the exercise of counterstrike capabilities. However, construction costs run several times higher than those of conventional submarines, and their maintenance and operation require specialized technology and personnel.

Calls for nuclear submarine acquisition have also reportedly been raised at expert panels convened to discuss the revision of the three security documents.

The Yomiuri noted that cautious voices remain, and that the Japanese government plans to carefully weigh recommendations from the expert panels as well as opinions from the ruling party before reaching a conclusion.

Earlier, in June, Nippon Ishin no Kai — a party that forms part of Japan's coalition government alongside the Liberal Democratic Party — submitted a proposal to the government calling for a review of the ban on nuclear weapons introduction and urging the adoption of nuclear-powered submarines. The party emphasized the extended deterrence provided by the United States' nuclear umbrella and requested a realistic review with an eye toward reconsidering the "no introduction" principle among Japan's three non-nuclear policies.