Decarbonizing maritime transport is an essential topic for the maritime industry and its stakeholders. Switching from conventional fuels to more environmentally friendly options is the most promising solution in the near term, and hydrogen plays a key role with its carbon-free structure. However, the need for more legislation and experience in the industry on this matter makes it difficult to establish definitive rules for using hydrogen as fuel on ships. This chapter provides a comprehensive overview of the current state of hydrogen legislation within the maritime industry by highlighting key developments, challenges, and future directions.