There is growing pressure on the maritime sector to embrace sustainable energy sources and cut greenhouse gas emissions. With an emphasis on marine applications, this paper provides an extensive overview of the developments in the use of hydrogen and biodiesel as dual-fuel alternatives in internal combustion engines. While hydrogen contributes to high combustion efficiency and zero-carbon output, biodiesel is compatible with current diesel engines and lowers CO₂ and SOx emissions. By utilizing the advantages of both fuels, the dual-fuel combination promotes better thermal performance and cleaner combustion. In order to assess engine performance, emission characteristics, and economic viability, this study combines simulation results, experimental findings, and life cycle assessments (LCA). There is discussion of important issues like NOx production, infrastructure constraints, and fuel storage complexity. Future research avenues are also described, such as integration with renewable electrolysis, onboard hydrogen reforming, and engine control optimization. The results support the role of biodiesel-hydrogen systems in attaining a low-emission, sustainable maritime future and highlight their potential to decarbonize marine transportation.