There is growing interest in the role for synthetic e-fuels produced using green hydrogen, as a potential pathway for decarbonising marine transport. E-methanol is the most market ready marine e-fuel and could become increasingly competitive by the mid-2030s, using biomass derived CO2. On the other hand, considerable barriers still need to be overcome for e-ammonia to be adopted as a shipping fuel. E-fuels are forecast to account for 14% of global marine fuel demand by 2050 in our base case outlook, displacing nearly 0.8 million b/d of marine fuel sales. Meeting the IMO 2050 decarbonisation target would require e-fuels marine market share to rise to just over 40%, increasing shipping’s share of global low carbon hydrogen supply from 7% to 20% by 2050. However, further increases in green hydrogen production would be challenging, due to the requirements for additional renewable energy capacity.