Ammonia is gaining traction as a potential marine fuel, particularly 'Green Ammonia' produced from renewable sources. It offers a promising alternative with zero CO2 emissions, aligning with the shipping industry's goals for sustainability. Despite challenges like toxicity and lower energy density, advancements in combustion technology and fuel cells aim to enhance safety and efficiency. Different types of ammonia, including Green, Blue, and Grey, cater to varying environmental concerns. Green Ammonia, generated using renewable energy, stands out for its minimal carbon footprint. The emission profiles of ammonia types differ, with Green Ammonia exhibiting significantly lower CO2 emissions. While technology readiness for ammonia-fueled engines is still evolving, recent milestones like the Fortescue Green Pioneer's ammonia-powered vessel showcase progress. Operational aspects, storage, handling, and necessary safety measures are critical for integrating ammonia as a viable maritime fuel. Collaborations between companies like Amogy and Yanmar highlight the industry's commitment to decarbonizing marine fuel technology, showcasing a positive outlook for the future of 'Green Ammonia' in shipping.