Ammonia is a zero-carbon fuel that has attracted considerable interest. The compound has high volumetric energy density and is easy to store and transport. Despite this, a proper study is necessary to ensure safety because ammonia fuel will likely be applied first to ammonia carriers. In this study, hazard identification (HAZID) was performed to identify the risk of the ammonia fuel supply system and preventive/mitigation measures were suggested to minimize the risk. The analyzed system scope was the ammonia fuel supply system from a fuel service tank on the deck to the front of the engine. The nodes with the most scenarios were the fuel service tank and the fuel supply line. The main factors included internal factors, such as design defects, malfunctions, and operational errors, and external factors, such as impact, thermal stress, hogging, and sagging. Recommendations are provided to reduce the risk of accident scenarios, including safety devices/alarm devices in process systems, system layout configurations, and heat and gas dispersion analysis. The results are expected to help predict/minimize damage regarding ammonia fuel supply system design, operational safety, and potential risks.