The maritime sector faces an unprecedented challenge to reduce its environmental pollution, particularly greenhouse gas emissions. Maritime decarbonisation is a complex issue that requires multidimensional thinking and a combination of a wide range of methods as a solution. One of the most important solutions is the use of alternative fuels, and hydrogen is considered a promising fuel to achieve the International Maritime Organization (IMO)’s 2050 net-zero targets. However, it is also crucial to assess the holistic environmental impacts of hydrogen from a life cycle perspective. In this study, comprehensive research on the use of hydrogen in the maritime sector was carried out, and potential losses and shortcomings have been analysed along with the gains. Existing studies show that hydrogen has great potential to be a lasting solution to decarbonisation, particularly if it is produced through renewable energy sources.