This chapter explores the intersection of hybrid threats and maritime security in the context of critical maritime infrastructure (CMI). The chapter examines the theoretical underpinnings of hybrid threats, drawing from both realist and constructivist perspectives offering a comprehensive understanding of their strategic implications. A significant emphasis is placed on Russian New Generation Warfare (NGW), highlighting its asymmetric strategies, which aim to destabilize the Western-led international order. The Black Sea serves as a paradigmatic case study, illustrating the intricate interplay between geopolitical competition and the vulnerabilities of maritime infrastructure. By situating these threats within broader international relations frameworks, the chapter underscores the challenges posed by hybrid threats to global maritime governance and the rule-based order. Policy recommendations include enhancing resilience, improving strategic communication, and fostering cooperative frameworks to mitigate risks and protect CMI against evolving hybrid threats. Keywords: hybrid threats, critical maritime infrastructure (CMI), Black Sea, New Generation Warfare (NGW).