Traditionally, ships navigated the oceans in relative isolation from the rest of the world. However, maritime navigation has become increasingly dependent on third parties due to new technologies such as satellite data transmission and shore-based support systems. In recent years, international shipping has faced growing challenges safeguarding its operations against emerging cybersecurity risks. Autonomous and unmanned vessels, the quintessential case of technology-dependent ships, are potentially at a higher risk of cyberattacks. Artificial intelligence-based systems and remote operation from shore-based control centers increase their vulnerability. However, paradoxically, the scholarship analyzing the implications of cyber-security of autonomous and unmanned vessels from a legal perspective is notably limited in scope. Thus, this Chapter analyzes the relevance of cybersecurity for autonomous ships, presents the threat landscape, and examines the existing international regulatory framework and standards. The Chapter concludes that even though the International Maritime Organization (IMO) and classification societies have developed cybersecurity standards and guidelines for conventional vessels, they are still not adjusted to emerging technologies such as autonomous ships. Therefore, new durable solutions must be developed to safeguard the operations of autonomous and unmanned ships from cyber threats