Black Liquor to Fuel (BL2F) process produces drop-in biofuels for aviation and shipping from black liquor, a side stream of chemical pulping industry. 83 % CO2 reduction compared to fossil fuels, and competitive production cost of 0.90 €/l for drop-in sustainable aviation fuel are received. A large deployment, using a variety of biomass, can yield >50 billion liters of advanced biofuels by 2050, then satisfying the EU demand for advanced biofuels for aviation (15 Mtoe) and shipping (30 Mtoe). First-of-a-kind Integrated Hydro Thermal Liquefaction (IHTL) process at pulp mills produces fuel intermediate for further upgrading in oil refineries. Biomass is converted to low oxygen content (<10 w-%) HTL-oil in water of reductive conditions at up to 400 ˚C, 300 bar. The expected energy yield is >85 %. Integrated hydrothermal HydroDeOxygenation (IHDO) will further upgrade HTL-oil to fuel intermediate (<5 w-% O2), classifying as bunker-like marine fuel or feedstock for high-quality aviation and marine fuels production. The process innovations of BL2F are: 1) combined salt separation and HTL-reactor, enabling direct upgrading of HTL-oil, 2) reforming of the aqueous phase to hydrogen, decreasing the need for external fossil hydrogen in IHDO, 3) integrating the process to pulp mill, offering cost reductions in treating of the gaseous and solid side streams by existing process installations. The BL2F is supported by CEPI, Avinor, and Rolls Royce and covers the whole value chain: The 6th largest producer in the world of bleached eucalyptus kraft pulp NVG, the leading biorefinery supplier Valmet, catalyst developer Ranido and Neste, the world’s largest producer of renewable diesel collaborate with excellent research partners; VTT, PSI, SINTEF, Tampere University, KIT, Brunel University London. LGI and industrial partners maximize the impact of the project. The ambitious goals and strong consortium strengthens European leadership in renewable biofuels and climate protection.