Republic of Korea
The Republic of Korea (South Korea) boycotted the negotiations on the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017 and has consistently voted against the annual UN General Assembly resolutions on the Treaty, including in 2025. It may sign and ratify or accede to the TPNW, but will have to make changes to its policies and practices to become compliant.
TPNW Status
| Key weapons of mass destruction treaties | ||
|---|---|---|
| NUCLEAR WEAPONS | ||
| Party to the TPNW | No | |
| Party to the NPT | Yes (Ratified 1975) | |
| Ratified the CTBT | Yes (Ratified 1999, Annex 2 state) | |
| Party to an NWFZ | No | |
| CSA with the IAEA | Yes (In force 1975) | |
| AP with the IAEA | Yes (In force 2004) | |
| BIOLOGICAL AND CHEMICAL WEAPONS | ||
| Party to the BWC | Yes (Ratified 1987) | |
| Party to the CWC | Yes (Ratified 1997) | |
| TPNW Art. 1(1) prohibitions: Compatibility in 2025 | ||
|---|---|---|
| (a) | Develop, produce, manufacture, acquire | Compatible |
| Possess or stockpile | Compatible | |
| Test | Compatible | |
| (b) | Transfer | Compatible |
| (c) | Receive transfer or control | Compatible |
| (d) | Use | Compatible |
| Threaten to use | Compatible | |
| (e) | Assist, encourage or induce | Non-compatible |
| (f) | Seek or receive assistance | Compatible |
| (g) | Allow stationing, installation, deployment | Compatible |
| TPNW voting and participation | |
|---|---|
| UNGA resolution on TPNW (latest vote) | Voted no (2025) |
| Participated in 3MSP (2025) | No |
| Participated in 2MSP (2023) | No |
| Participated in 1MSP (2022) | No |
| Average MSP delegation size (% women) | N/A |
| Adoption of TPNW (7 July 2017) | N/A |
| Participated in TPNW negotiations (2017) | No |
| Negotiation mandate (A/RES/71/258) | Voted no |
| Fissile material | |
|---|---|
| Nuclear facilities | Yes |
| Fissile material production | No |
| HEU stocks | Cleared |
| Plutonium stocks | No |
| SQP with the IAEA | No |
Latest developments
In the Conference on Disarmament in February 2025, the Republic of Korea (South Korea) reiterated its call for the Democratic People’s Republic of Korea (North Korea) ‘to abandon its weapons of mass destruction and ballistic missile programmes in a complete, verifiable, and irreversible manner and return to dialogue for denuclearization’.1
At the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Preparatory Committee meeting in April 2025, South Korea argued that North Korea ‘continues to present the most significant challenge to the NPT’. ‘We strongly condemn [North Korea]’s illegal nuclear and ballistic missile programmes, which constitute clear violations of multiple UN Security Council resolutions and the NPT itself,’ it said.2
In the general debate of the 80th session of the UN General Assembly in September 2025, the President of South Korea, Jae Myung Lee, said that global denuclearization ‘cannot be achieved in the short term’. ‘The international community must gather its wisdom in a pragmatic and phased solution beginning with a “stop” in the sophistication of nuclear and missile capabilities, going through a “reduction” process and reaching “dismantlement”,’ he said.3
In October 2025, the President of the United States, Donald J. Trump, announced that he had granted South Korea approval to enrich uranium and reprocess spent nuclear fuel for nuclear-powered submarines. This would give South Korea a latent nuclear weapons capability.4
In 2023, the then-President of South Korea, Yoon Suk Yeol, said that, if the threat posed by North Korea increases, his country might consider developing its own nuclear weapons or asking the US to redeploy such weapons to the Korean Peninsula. ‘It’s possible that the problem gets worse and our country will introduce tactical nuclear weapons or build them on our own,’ he said. ‘If that’s the case, we can have our own nuclear weapons pretty quickly, given our scientific and technological capabilities.’5
The US withdrew all of its nuclear weapons from South Korea in 1991. As a State Party to the NPT, South Korea is legally barred from ever manufacturing or otherwise acquiring nuclear weapons.
In 2023, South Korea and the United States issued the Washington Declaration, deepening cooperation between the two countries on nuclear weapons planning in the region. The United States stated that its ‘commitment to extend deterrence to [South Korea] is backed by the full range of US capabilities, including nuclear’.6
Recommendations
-
South Korea should renounce the possession and potential use of nuclear weapons on its behalf, and ensure that nuclear weapons do not have a role in its defence posture.
-
South Korea should comply with its existing obligation under Article VI of the NPT and pursue negotiations in good faith on nuclear disarmament.
-
South Korea should urgently adhere to the TPNW. Until it is in a position to do so, it should welcome the TPNW as a valuable component in the global disarmament and non-proliferation architecture, work with the Treaty's states parties on practical steps towards disarmament, and attend the meetings of states parties as an observer.