In the current research work, the generation of carbon rich materials from abundant low-cost lignocellulosic waste was assessed using two thermal conversion techniques, namely hydrothermal carbonization (HTC) and slow pyrolysis. Herein, the impact of temperature variation on the physio-chemical properties of hydrochars and biochars produced from the raw olive pomace (ROP) was investigated by multiple analysis techniques. Results suggest that hydrochars present the highest solid yields with interesting final content in functional groups. On the other hand, biochars issued from slow pyrolysis presented important carbon percentage and low volatile matter content. FTIR analysis suggested a significant alteration of the surface after pyrolysis process compared to HTC.