This paper examines how Russia’s invasion of Ukraine reshaped the European Union’s energy security and foreign policy through the REPowerEU agenda. It argues that REPowerEU is more than a crisis-response mechanism: it represents an attempt to align energy diversification, decarbonisation and geopolitical strategy within a more coordinated EU framework. The paper assesses the early dividends of this approach, including reduced dependence on Russian gas, expanded energy partnerships, and the emergence of collective mechanisms such as the EU Energy Platform. At the same time, it highlights the challenges of managing new dependencies on LNG suppliers, critical raw materials, transit routes and regional geopolitical actors. The paper concludes that REPowerEU’s long-term success depends on whether the EU can institutionalise energy diplomacy as a core component of its foreign and security policy while maintaining its climate ambitions and strategic autonomy.