Iran has multiple nuclear sites comprising declared facilities involved in the nuclear fuel cycle and undeclared sites suspected of nuclear weaponization efforts. Key declared sites include:

• Natanz: Iran's primary uranium enrichment site with underground bunkers, heavily targeted by attacks.
• Fordow: Underground enrichment site inside a mountain, capable of housing about 3,000 centrifuges.
• Isfahan Nuclear Technology Center: A large complex with uranium conversion, fuel fabrication, and research reactors.
• Bushehr: Iran's only commercial nuclear power plant on the Persian Gulf coast.
• Arak: Heavy water reactor site under modification and heavy water production plant.
• Tehran Nuclear Research Center: Research reactor site.
• Darkhovin and Sir: New nuclear power plants under construction.

There are also undeclared sites and facilities related to military nuclear weapon development, including facilities near Parchin and various research and production centers linked to explosive testing and nuclear weapon components. In total, Iran operates and maintains a complex network of approximately 10-15 major nuclear-related sites scattered over several provinces, including centers for uranium enrichment, heavy water production, nuclear research, and power generation. Notably, some of the undeclared sites have been targeted and damaged by Israeli airstrikes in 2025. Thus, Iran has at least a dozen significant nuclear sites with diverse functions ranging from peaceful nuclear energy production and research to uranium enrichment and suspected weaponization activities.