A tungsten carbide ceramic containing 5 vol% silicon carbide was hot pressed to full density at 1820 °C. A small amount of transient liquid phase based on W-C-Si-O facilitated oxide removal in the reducing environment and favoured the development of a bimodal microstructure containing sub-micrometric grains with square or rod-like morphologies. These microstructural features led to outstanding mechanical properties from room to elevated temperatures. For the first time, WC-materials were characterized up to 1500 °C exhibiting flexural strength over 1 GPa in the whole temperature range and fracture toughness from 7 to 15 MPa·√m.