This study assessed the Strategic Communication and Power Politics in Nuclear Diplomacy: Analysing the UK, Germany and France's UN Security Council Snapback Sanctions on Iran. The communication theory of international signalling was anchored in this study. This study adopted the Interpretivist research philosophy. The research design employed was a qualitative exploratory design. The population of the study comprises foreign policy documents, communiqués, press releases, official statements, and policy reports from the governments of the UK, Germany, France, and Iran, as well as records from international organizations such as the United Nations and the European Union, estimated at 520 official documents and public statements published between 2015 and 2024 (European External Action Service [EEAS], 2024). The sample size for the study consists of 50 purposively selected documents and statements, drawn from official publications, policy briefs, and international news archives that specifically address the E3’s role in the Iran nuclear negotiations. The sampling technique and process involved three stages: identifying official repositories (such as the UN Digital Library, EEAS archives, and the UK Foreign, Commonwealth and Development Office); filtering materials by relevance to the E3–Iran nuclear discourse; and selecting those that represent both governmental and international perspectives to ensure a balanced analytical scope. The method of data collection relied on documentary analysis, focusing on retrieving textual materials, official records, and secondary data from credible institutional sources and peer-reviewed literature. The method of data analysis employed was thematic and discourse analysis. The findings revealed that The study found that the United Kingdom, Germany, and France (E3) consistently employed strategic communication to project unity, legality, and credibility in managing the UN Security Council snapback sanctions, using coordinated rhetoric, public diplomacy, and symbolic actions to frame their enforcement as multilateral, responsible, and norm-driven. The study concluded that the E3 effectively employed strategic communication to project unity, legality, and credibility, demonstrating that coordinated messaging and symbolic actions are central to influencing perceptions and reinforcing authority in nuclear diploma. The study recommended that E3 should strengthen coordinated strategic communication through the European External Action Service (EEAS) and national foreign ministries to maintain consistent messaging and reinforce credibility in international diplomacy