This report analyses regulatory, technological, and financial opportunities and barriers to the adoption of green hydrogen and ammonia in decarbonising shipping and port infrastructure. The main barriers are the mismatch in timeline between stakeholders in developing technology and infrastructure, establishment of safety standards and regulatory frameworks, and a “chicken-and-egg” situation in financing market off-take structures. Opportunities relate to harmonising national, regional, and international ambitions and policy planning, sector coupling, and establishment of green corridors.