Japanese classification society, ClassNK, has recently published an updated edition of its Guidelines for Ships Using Alternative Fuels, expanding the safety requirements to cover the usage of hydrogen as a fuel source. The guidelines aim to ensure the safe installation, controls, and use of alternative fuels like methanol, ethanol, LPG, ammonia, and now hydrogen, with a focus on minimizing risks to ships, crew members, and the environment. This new edition, version 3.0, incorporates the IGF Code's provisions and introduces additional requirements specific to the properties of hydrogen fuel and its associated hazards. The guidelines provide detailed considerations for the safety of hydrogen-fueled ships, addressing key areas such as preventing explosions triggered by hydrogen's high flammability and mitigating the impacts of potential hydrogen leaks on crew members and the marine ecosystem. ClassNK's commitment to supporting the industry's transition to zero-emission solutions is evident through its provision of safety requirements and design guidance for alternative-fueled ships. By offering Transition Support Services, ClassNK aims to facilitate the adoption of eco-friendly vessels by assisting customers in meeting the necessary safety standards and embracing innovative designs that promote environmental sustainability. The updated guidelines underscore the importance of proactive measures in ensuring the safe and efficient operation of ships using alternative fuels, including the increasingly vital hydrogen option.