Hydrogen is believed to be a promising decarbonisation vector. An optimal hydrogen supply-chain network achieving net-zero emissions in ASEAN by 2050 is determined. A logistic profile for decarbonisation and declining costs with technological advances are assumed. It is found that the region has the potential to fully decarbonise its power sector with renewable energy if a regional power grid is installed. A mix of green (from surplus renewable power), blue (from natural gas) or orange (from biomass) hydrogen, the latter two with carbon capture and sequestration, meets industry, transport and power (without a regional power grid) sector demands. Results show that available biomass is insufficient to meet decarbonisation targets beyond 2045 without green hydrogen. Prioritising energy security and sustainability has minimal incremental costs compared to importing liquefied natural gas for blue hydrogen production. Optimal production locations are Myanmar, Cambodia for green hydrogen, and Indonesia, Vietnam for orange and blue hydrogen.