Executive Summary
- What is new: On 28 August 2025, the UK, France and Germany (the E3) formally notified the UN Security Council (UNSC) regarding Iran’s noncompliance with the Joint Comprehensive Plan of Action (JCPOA), initiating the sanctions “snapback” mechanism under UNSC Resolution 2231 (2015).
- Why it matters: The UNSC sanctions against Iran, which the security council had put in place before the JCPOA’s implementation day in 2016 as part of a global effort to curb Iran’s development of nuclear weapons, will be automatically reimposed on 28 September 2025 at midnight GMT, unless a further UNSC resolution is adopted or the E3 reverses its position that Iran is in violation of the JCPOA. This is the most significant development in relation to the Iran sanctions since the first Trump Administration withdrew the US from the JCPOA in 2018.
- What to do next: The next few weeks will define the future of UN sanctions on Iran. Companies with continued exposure to Iran should consider (i) reassessing their businesses to identify the potential impact of the “snapped back” sanctions, as implemented by United Nations member states, and (ii) reevaluating their existing sanctions compliance programmes to ensure they can identify and mitigate risks.
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Background
Between 2006 and 2015, the UNSC adopted a series of resolutions applying economic, financial and trade-related sanctions to Iran in response to its nuclear programme. Specific jurisdictions, such as the United States and the European Union, also imposed on Iran during that period additional sanctions that extended well beyond the mandate of the UNSC.1
In 2015, the UNSC adopted Resolution 2231, which endorsed the JCPOA as a “comprehensive, long-term and proper solution to the Iranian nuclear issue” and which eight parties (China, France, Germany, Russia, the European Union, the United Kingdom, the United States and Iran) (jointly, the JCPOA parties) agreed upon.
Resolution 2231 provided for the termination of certain sanctions in exchange for Iran undertaking commitments related to its nuclear program (e.g., monitoring by the International Atomic Energy Agency (IAEA)), and created a timetable for the JCPOA’s implementation.2 Resolution 2231 also provided for its termination on 18 October 2025, and the conclusion of the UNSC’s consideration of the Iranian nuclear issue, if the previous UNSC resolutions had not been reinstated by that time.
Diplomatic relationships between certain JCPOA parties and Iran have significantly deteriorated in the past few years and, on 28 August 2025, the E3 issued a joint statement3 that documented that since 2019 Iran has:
- Exceeded JCPOA limits on enriched uranium, heavy water and centrifuges.
- Restricted the IAEA’s ability to conduct JCPOA verification and monitoring activities.
- Abandoned the implementation and the ratification process of the Additional Protocol to its Comprehensive Safeguards Agreement.
The E3 also highlighted that efforts to restore compliance, including diplomacy and the JCPOA’s dispute resolution mechanism, have not been successful.
The E3 stated that therefore it was notifying the UNSC that Iran was in breach of its commitments under the JCPOA, triggering what is referred to as the “snapback” mechanism,4 which is the means through which the effects of the prior UNSC sanctions will resume.5
For companies and individuals who resumed their business with Iran following the implementation of the JCPOA and the associated sanctions relief, or continued to do business with Iran throughout the period after 2006, the impact of the restoration of the previous sanctions regime may be significant.
We outline below three specific points of attention for companies as they consider their next steps: (i) the timeline for the restored sanctions; (ii) non-retroactivity; and (iii) the scope of reimposed sanctions.
Timeline
UNSC Resolution 2231 sets out the snapback process, providing that, once the UNSC has been notified by a JCPOA party that Iran is in violation of its obligations under the JCPOA:
- Within 10 days of the notification to the UNSC:
- a member of the UNSC will propose a draft resolution to maintain the termination of the effects from the sanctions; or
- the president of the UNSC can propose such a draft resolution if no member of the UNSC has submitted such draft.
- Within 30 days of the notification to the UNSC, the notifying party can inform the UNSC that the issue is resolved and the termination of the effects of the sanctions will remain.
- If the UNSC does not adopt a resolution within 30 days and the notification of noncompliance has not been withdrawn, then the USNC sanctions previously imposed on Iran will apply in the same manner as before.
Reportedly, on 8 September 2025, South Korea, which holds the presidency of the UNSC, finalized a draft resolution for consideration by the UNSC, but no date has been set for a vote.6 The UNSC must adopt this resolution by 28 September 2025 at midnight GMT or the sanctions will “snap back.”
Non-retroactivity
For companies potentially impacted by a snapback, Resolution 2231 notably provides that the sanctions that are “snapped back” do not apply retroactively to contracts signed prior to the date when the sanctions resume, provided the contracts are in compliance with the JCPOA and the relevant UNSC resolutions.
Additionally, Resolution 2231 explicitly states that the “snapped back” sanctions do not aim to harm companies that engaged in business with Iran consistent with the JCPOA and Resolution 2231, and encourages states to take action to mitigate unintended harm.
Scope of the Restored Sanctions
The sanctions that are subject to the snapback mechanism are those contained in the following UNSC resolutions: 1696 (2006), 1737 (2006), 1747 (2007), 1803 (2008), 1835 (2008), 1929 (2010) and 2224 (2015). They cover a range of different matters, including the reimposition of asset freezes on a significant number of Iranian persons (including several Iranian banks), trade restrictions on a range of military goods and goods related to Iran’s nuclear and ballistic missile programme, and targeted investment restrictions. There is also the possibility that, in parallel, UN member states, such as the UK and EU member states, will reimpose on Iran sanctions that extended beyond what UNSC resolutions had required prior to the JCPOA. The exact scope and contours of UK (at the time the JCPOA was adopted, the UK was still a member of the EU) and EU sanctions that might snap back remain unclear.
When the United States withdrew from the JCPOA in 2018, although the country chose not to trigger the snapback of UNSC sanctions, the US generally reinstated its autonomous sanctions program as the program existed prior to the JCPOA, albeit in a phased, two-tiered approach (with certain measures being reimposed immediately, while others were phased in over a period of several months). Over the ensuing years, the United States adopted additional sanctions targeting Iran. The EU and the UK may adopt a similar phased approach to any sanctions that snap back.
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1 The relevant UNSC resolutions are Resolution 1696 (2006), Resolution 1737 (2006), Resolution 1747 (2007), Resolution 1803 (2008), Resolution 1835 (2008), Resolution 1929 (2010) and Resolution 2224 (2015).
2 See the UN’s additional information on Resolution 2231.
3 UK Foreign, Commonwealth & Development Office, “E3 Joint Statement on Iran: Initiation of the Snapback Process” (28 August 2025).
4 See the E3’s letter to the president of the UNSC.
5 As provided in paragraph 11 of Resolution 2231, any JCPOA participant can notify the UNSC of Iran’s nonperformance.
6 Reuters, “South Korea Takes Next UN Step in Iran Sanctions Snapback Process” (8 September 2025).
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