https://www.japantimes.co.jp/news/2026/09/11/japan/koizumi-japan-us-nuclear-submarines/
Defense Minister Shinjiro Koizumi has said that Japan is keeping all options on the table when it comes to discussions of Japan acquiring nuclear-powered submarines. | JIJI
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...Japan not ruling out nuclear subs, days after U.S. offers positive view
Defense Minister Shinjiro Koizumi on [
Sept 11, 2026] reiterated that Japan is not ruling out acquiring nuclear-powered submarines, days after a U.S. Navy official reportedly offered a positive assessment of the move.“Regarding nuclear-powered submarines, we will proceed with our consideration of not ruling them out as an option,” Koizumi told a regular news conference. Tokyo is weighing acquiring such submarines in revisions to its three key security documents set to come by the year’s end.
Koizumi’s remarks came after an unidentified U.S. Navy official [at Pearl Harbor - see Trump (diplomatic as ever's) revenge on Japan], citing Tokyo’s expertise in nuclear energy technology, told Japanese and South Korean media this week that Tokyo should consider acquiring nuclear submarines.
Asked about how the vessels might fit into Japan’s security strategy, the defense chief noted the pros and cons, saying that while nuclear-powered submarines are capable of extended patrols and are said to have several times the speed of conventionally powered submarines, they are less quiet underwater, expensive and require specialized expertise for maintenance, repair and operation.
Japan currently operates a fleet of 23 diesel-electric attack submarines, but has long avoided the more expensive and politically fraught option of nuclear-powered vessels.
Calls for Tokyo to acquire nuclear boats gained steam after an expert panel recommended in September last year that Tokyo develop vessels with “next-generation” power sources and vertical launching systems for long-range missiles. The ruling Liberal Democratic Party-Japan Innovation Party bloc effectively codified this push in their October coalition agreement.
Although neither the expert panel nor the coalition deal directly mentioned nuclear-powered submarines, Koizumi and other Japanese officials have repeatedly refused to rule out any options when it comes to nuclear submarines, as Tokyo looks to boost its defense capabilities.
Koizumi added to the speculation in November, when he touched on South Korea’s deal with the U.S. to secure nuclear vessels, noting that “all the surrounding countries have nuclear submarines.”
In June, the JIP also reignited the debate when it submitted a proposal to the government that called for the swift introduction of nuclear-powered submarines, citing China’s constant naval expansion into the Pacific.
The Chinese Navy is moving toward an all-nuclear-powered submarine fleet, U.S. naval officials say, a monumental shift that will give ammunition to proponents of Japan developing its own nuclear subs.
2 comments:
Hi Pete,
This is totally expected following the US ‘approval’ of SK nuclear submarines, as Japan will maintain parity with SK. This will also enable both nations to counter PLAN, NK and Russian naval units in the Sea of Japan (East Sea) and the Philippines Sea.
I also predict that both South Korea and Japan will have SSBNs with nuclear weapons by 2050.
I’ve done a bit of research into SK nuclear powerplant R&D, but need to read up on Japanese advancements.
Hi Shawn
I agree with all your points and have posited the SSBN theory (especially for SK SSBNs as deterrents against NK) in the past.
If SSN patrol patterns for Japanese and SK extended far into the central Pacific this would reduce the USN's problem of its 40% to 50% shortfall in US SSN numbers.
Also with J and SK building SSNs this takes the pressure off the US ever having to deliver Virginias to Australia promised by the US under AUKUS.
Australia will pay $140 Billion though to 2045 for facilities to host US SSNs in Western Australia but that money is more protection money for the US alliance and a way of winning Aus Federal+State Elections than adding an extra base area for US subs. US subs have ALREADY been visiting Western Australia for 20 years, if not longer, without a $multi-billion "Rotation" cash outlay..
Also the US already has ample SSN bases in the Indo-Pacific - so doesn't need Australia's $140 Billion. The US has 3 or 4 SSN bases on the US West Coast, also Hawaii, Guam, Yokosuka Japan, Diego Garcia and "Naval Support Activity" (disguised name for a huge multi-purpose base) in Bahrain.
See https://en.wikipedia.org/wiki/United_States_Navy_submarine_bases#Active_bases
On Japanese Uranium enrichment for all types of reactors and nuclear weapons: AI advises "Japan conducts commercial uranium enrichment primarily through the gas centrifuge facility operated by Japan Nuclear Fuel Limited (JNFL) in Rokkasho, Aomori Prefecture".
Also https://en.wikipedia.org/wiki/Rokkasho_Reprocessing_Plant "is a nuclear reprocessing plant with an annual capacity of 800 tons of uranium or 8 tons of plutonium.[1] It is owned by Japan Nuclear Fuel Limited (JNFL)" Plutonium being an ingredient for future Japanese nuclear weapons with SK seeing an equivalent weapons program as essential.
Pete
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