This chapter traces the transformation of the EU's gas strategy from a historical dependence on Russian supplies to a path of decoupling and reshaping the energy security architecture. It first explains how the crises of 2006 and 2009, and then the pressures of 2021/22, exposed the vulnerability of reliance on Russian gas flowing to Europe via Ukrainian pipelines, and how European legislative frameworks evolved from internal gas market directives to supply security regulations, aiming to enhance the flexibility, integration, and crisis-resilience of the European market. The chapter then presents the pillars of the European energy strategy REPowerEU: diversification of sources, demand rationalization, and accelerating the transition to renewable energy. It illustrates the Member States' shift towards new suppliers and the expansion of the European infrastructure to accommodate liquefied natural gas (LNG). Finally, it discusses the growing interest of the EU in the Eastern Mediterranean as a promising but constrained route, hampered by limited liquefaction capacity, geopolitical tensions, and growing domestic demand.