Mitsui O.S.K. Lines (MOL) along with Namura Shipbuilding and Mitsubishi Shipbuilding have received approval in principle (AiP) from Nippon Kaiji Kyokai (ClassNK) for a novel large-size ammonia-powered carrier design. The vessel aims to support the increasing adoption of ammonia as a sustainable, zero-carbon fuel and a carrier for hydrogen in power plant transitions. This groundbreaking carrier, developed since 2021, boasts larger cargo tanks than traditional very large gas carriers (VLGCs) and very large ammonia carriers (VLACs), allowing for more eco-friendly transport and higher cargo capacity while utilizing ammonia as fuel. One of the key aspects of this innovative carrier is its ability to conform to entry restrictions at major power plants in Japan while maintaining compatibility with existing VLGCs in terms of connections to power plants and ammonia supply terminals during loading and unloading operations. ClassNK's thorough review of the basic plans and hazard identification study results, integrated into the basic design, has enabled the progression to the detailed design phase. Notably, specific focus was given to addressing concerns regarding ammonia toxicity, with robust countermeasures implemented to ensure the vessel's safety standards. This milestone in sustainable marine technology signifies a significant step towards a greener future in the shipping industry, aligning with global efforts towards decarbonization and energy transition. The collaborative efforts of MOL and its partners in developing an ammonia-powered carrier demonstrate a commitment to innovation and environmental responsibility in maritime operations.