We provide an overview of each regime below.

A. UN sanctions reimposed

As of 27 September 2025, the snapback reinstates six key UNSC Resolutions. These measures restore comprehensive restrictions and prohibitions, including:

• UNSC 1696 (2006): Targeting Iran’s nuclear development by demanding a halt of its uranium enrichment program.
• UNSC 1737 (2006): Asset freezes and restrictions on nuclear-related goods.
• UNSC 1747 (2007): An expanded arms embargo and financial restrictions.
• UNSC 1803 (2008): Call on states to exercise vigilance in providing public support for trade with Iran and to also exercise vigilance over financial institutions active in Iran.
• UNSC 1835 (2008): Reaffirmed existing sanctions.
• UNSC 1929 (2010): Further broadened sanctions, including a ban on ballistic missile technology and a comprehensive arms embargo.

All UN member states must fully implement sanctions imposed by the UNSC, so these measures apply, in effect, on a global basis.

B. EU autonomous measures:

On 29 September 2025, the EU reinstated its own autonomous measures on Iran which were in place prior to the implementation of the JCPOA through:

• Council Regulation (EU) 2025/1975, accessible here.
• Council Implementing Regulation (EU) 2025/1980, accessible here.
• Council Implementing Regulation (EU) 2025/1982, accessible here.

The reinstated measures, amongst other things, reintroduce the following restrictions and prohibitions:

• Financial sector: An asset freeze on the Central Bank of Iran and other major Iranian commercial banks as well as a SWIFT ban.
• Transfers of funds: Subject to licensing requirements and exceptions, there is now a prohibition on transfers of funds between EU financial / credit institutions and Credit and financial institutions or bureaux de change domiciled in Iran or, in certain instances, elsewhere or their branches or subsidiaries.
• Targeted sanctions: Travel bans and asset freezes for listed individuals and entities, with a prohibition on making funds or economic resources available to them.
• Various trade, financing, investment and services restrictions in sectors involving Iranian crude oil, natural gas, petrochemical products and key energy sector equipment, precious metals, certain naval equipment and specific software.
• Transport sector: Restrictions preventing Iranian cargo flights from accessing EU airports and a prohibition on the maintenance of vessels and aircraft carrying prohibited goods.
• Other restrictions: Prohibitions relating to transactions in Iranian Government bonds and others.

C. UK Autonomous Measures:

Concurrently with the EU, the UK has also reinstated sanctions on Iran through The Iran (Sanctions) (Nuclear) (EU Exit) (Amendment) Regulations 2025, see here, amending the Iran (Sanctions) (Nuclear) (EU Exit) Regulations 2019.

The amendments entail sanctions on individuals and entities. They target 71 individuals and organisations linked to Iran’s nuclear programme, including major financial institutions and energy companies, including asset freezes, director disqualifications and travel bans.

Currently, the UK government has not yet reinstated sectoral sanctions on Iran, at the same scale as the EU regime. However, it has stated its intention to introduce additional measures in due course, focusing on key sectors including finance, energy, shipping, and software.

In addition, for the purposes of supporting the structured completion of prior transactions, the Office of Financial Sanctions Implementation (OFSI) has issued four general licences authorising, subject to certain conditions, the following activities for a limited period of time:

• the wind down of transaction with specified UK-based Iranian banks, accessible here.
• the wind down of transactions with certain Iranian banks established both inside and outside Iran, accessible here.
• the wind down or divestment of transactions involving the Iran Insurance Company and the National Iranian Oil Company, International Affairs Ltd, accessible here.
• The continued provision of goods, services and financing regarding the Shah Deniz gas project, accessible here.

Finally, OFSI also published FAQ 168 to clarify that all specific licences issued by HM Treasury under the UN regime prior to 2015 have ceased to have effect upon the designated person being delisted and new OFSI licence applications should be made where needed. See here.

D. EU and UK Blocking Regulations remain in force

Although the US welcomed the activation of the snapback mechanism, the EU and UK Blocking Regulations in relation to Iran (and Cuba) currently remain in place to counter the extraterritorial effect of US secondary sanctions.

It remains to be seen whether the EU and UK will scale back the blocking effect of the EU and UK Blocking Regulations in the coming weeks.

For more details, refer to the Council of the EU’s press release here and the UK Government’s press releases here and here