The demand for hydrogen-fuelled marine travel and transportation is on the rise, and in response, classification societies like ClassNK are playing a pivotal role in driving innovation while upholding safety standards. Headquartered in Tokyo and Chiba, Japan, ClassNK is at the forefront of providing technical services for the survey and classification of ships and marine structures as a third-party certification body. Apart from their traditional role, ClassNK is actively involved in supporting the adoption of alternative fuels, particularly hydrogen, and the development of ships that run on these fuels. By assessing safety measures, offering crucial information, and issuing rules and guidelines, ClassNK is enabling developers to navigate the complex landscape of alternative fuel ships. The emphasis on hydrogen as a sustainable marine transportation fuel underscores the industry's shift towards greener practices and the importance of organizations like ClassNK in facilitating this transition.