This chapter explores Bulgaria’s role in regional cooperation within the Black Sea, emphasizing the geopolitical, economic, and strategic dimensions of its engagement. The Black Sea region, connecting Europe, Asia, and the Middle East, holds significant geopolitical and economic importance. However, the war in Ukraine and ongoing geopolitical tensions have disrupted traditional trade routes, redefined energy corridors, and heightened regional instability, compelling Bulgaria to reassess its regional partnerships and strategic priorities. The chapter provides an overview of regional cooperation frameworks such as the Black Sea Economic Cooperation (BSEC), the EU’s Black Sea Synergy (BSS), the Common Maritime Agenda (CMA), and the Three Seas Initiative (3SI), highlighting Bulgaria’s active participation and the challenges these initiatives face due to geopolitical rivalries and conflicting regional interests. It also examines Bulgaria’s evolving trade and investment relationships with Black Sea countries, noting the shift away from Russian economic dependence and toward stronger ties with Romania, Türkiye, and Ukraine. Strategic sectors such as transport, energy, and the blue economy are analyzed to demonstrate Bulgaria’s efforts to leverage its geographical position for regional connectivity and sustainable development. By analyzing Bulgaria’s approach to regional cooperation in the context of shifting geopolitical landscapes, the chapter underscores the importance of multilateral engagement for fostering stability, economic integration, and resilience in the Black Sea region.