As the marine sector pursues ambitious carbon reductions goals, green hydrogen, paired with PEM based fuel cells and battery energy storage technology show promise to accelerate industrial maritime decarbonization. Maritime vessels that operate on short routes and recharge regularly can achieve emissions free operations using batteries alone. In contrast, to maintain zero-emission levels over longer distances and for larger vessels, other technologies are required. Hydrogen fuel cells are making headway as one such option. However, there are challenges that must be overcome for hydrogen to become a viable solution for maritime transportation. This presentation will highlight challenges and opportunities when considering hydrogen as an energy carrier onboard a vessel. Topics covered will include hydrogen production, transportation, bunkering, storage onboard vessels, and maritime specific regulations. As rules and regulations for the marine industry are different from land-based applications, we will discuss how to adapt existing technology for maritime applications. Lastly, the presentation will cover technical aspects to support safety and energy efficiency in using hydrogen onboard a maritime vessel.