Maritime swarming, in which multiple vessels organise themselves as a team to achieve a common objective, is a relatively new phenomenon. Development of maritime swarming capabilities in Australia is primarily driven by defence investment, particularly in the areas of mine counter measures and persistent surveillance. There are also potential commercial applications for maritime swarms, for example, in reef monitoring and search and rescue. Developers and operators must comply with existing regulatory frameworks, but these were written for traditional crewed vessels and create complexity and uncertainty for emerging technology. This chapter draws on the existing literature to identify and address two key issues relating to the regulation of maritime swarms. The first issue, how to characterise maritime swarms and the impact on their regulatory treatment, is addressed by outlining the three categories available for commercial vessels (domestic commercial vessels, regulated Australian vessels) and foreign vessels and touching on the way defence vessels are regulated both in peacetime and wartime. The second issue, the relationship between regulation, explainability, and trust, is addressed by explaining the meaning of each term and then identifying how they interconnect. The chapter concludes by considering the types of regulatory reform required to support safe and trusted operations into the future, including legislative change, a focus on risk-based regulation, and the introduction of technical standards led by industry.