World · 2026-10-25 · Afternoon briefing

Japan weighs taboo nuclear submarine fleet

Japan’s prime minister, Sanae Takaichi, is seriously considering acquiring nuclear-powered submarines, a move long considered taboo. The proposal for the Maritime Self-Defence Force is a direct response to China’s expanding naval presence in the Pacific. While the defence minister argues Japan's pacifist constitution does not prohibit nuclear propulsion, the idea faces internal debate within the ruling coalition over its high cost.

The financial trade-offs are stark. A nuclear submarine costs up to three times more to purchase and four times more to operate than a conventional boat. For a similar outlay, one study found Japan could acquire six nuclear submarines or ten large conventional ones to supplement its current 22-boat fleet. This would allow only one or two nuclear boats to be deployed at any time, versus three of the conventional alternative.

Operational challenges are also formidable. A nuclear boat requires roughly double the crew of Japan's advanced Taigei-class submarines, a significant personnel challenge. Even if approved now, analysts estimate it would take over a decade to field the first vessel, with delivery unlikely before the late 2030s.

Summary written by Cup of News with AI from the sources below. Check the originals for the full story.

Read the sources

• Eye on China: Japan reopens taboo debate over nuclear-powered submarines
• South Korea, Japan move toward nuclear-powered submarines
• Japan Plans to Equip Submarines with Hypersonic Missiles
• Japan’s nuclear options under a wavering US umbrella
• Taigei-Class Submarine: Japan’s Silent Hunter for a New Era of Undersea Warfare

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