Upgrading of three different bitumens from bottom of crude oil distillation columns, a type of bitumen from side stream of a propane deasphalting (PDA) unit and bitumen extracted from domestic tar sand samples was investigated in supercritical water (SCW). Coke suppression was highest for tar sand bitumens. Low vacuum residue (VR), high amounts of lighter ends, low aromatics and lower viscosity of the feed decreased coke yields even if there were high amounts of asphaltenes in the feed. At long reaction times, yields and selectivities were similar for different feeds. Red mud, Fluid Catalytic Cracking (FCC) spent catalyst, FeSO4, Fe2O3 and a blend of FCC spent and FeSO4 were investigated as catalytic additives. The coke yield was lowest with the FCC spent catalysts. Highest liquid yield was obtained using red mud. For all feeds, shot type cokes were obtained. (C) 2019 Elsevier B.V. All rights reserved.