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The US will help South Korea build nuclear 'attack' submarines - here's what that means

November 15, 2025

South Korea and the United States have finalized an agreement for South Korea to construct nuclear-powered attack submarines, marking a major advancement in their defense partnership. The deal, which includes US approval and cooperation on nuclear fuel sourcing, emerges alongside recent trade negotiations that reduced reciprocal tariffs to 15% following South Korea's commitment to invest $350 billion in America. This submarine program aims primarily to counter North Korea's advancing nuclear capabilities and submarine development, while also serving as a US strategic tool to pressure both Pyongyang and Beijing.

Who is affected

  • South Korea (gaining nuclear submarine capability)
  • United States (partner in the agreement and potential construction location)
  • North Korea (primary target of the enhanced defense capability)
  • China (faces increased pressure from strengthened US-South Korea alliance)
  • Hanwha (South Korean conglomerate that owns the Philadelphia shipyard mentioned for potential construction)
  • South Korean voters (reassured by government response to North Korean threats)
  • Regional countries in East Asia (affected by the escalating arms race)

What action is being taken

  • The US is giving approval for South Korea to build nuclear-powered attack submarines
  • The US is working closely with South Korea to advance project requirements, including sourcing nuclear fuel
  • China is engaging with Seoul through diplomatic channels regarding the submarine agreement
  • North Korea is pursuing its own nuclear submarine programme (shown under construction in March 2025)

Why it matters

  • This agreement represents a significant shift in regional military dynamics and South Korea's defense posture. Nuclear-powered submarines provide substantial strategic advantages over diesel alternatives, including greater speed, range, and stealth capabilities that allow extended operations without surfacing. The deal elevates South Korea to a select group of nations with nuclear submarine capability, transforming it into a more substantial regional military player. Beyond countering North Korea's nuclear threats, the agreement serves broader US strategic interests by positioning South Korea as a proxy to apply pressure on both Pyongyang and Beijing amid rising tensions in East Asia. The move also reflects the escalating arms race on the Korean Peninsula and the complex geopolitical competition between the US and China for influence in the region.

What's next

  • The nuclear agreement between the US and South Korea must be adjusted to allow the US to provide nuclear fuel and establish parameters for its military use
  • Resolution is needed regarding the construction location dispute, with Trump indicating Philadelphia while South Korean officials maintain the submarines must be built locally where existing facilities can deliver them faster

Read full article from source: BBC