Rice is a widely consumed food product worldwide, and it generates an agro-industrial waste product called rice husk, which currently lacks economic value and is poorly managed due to its difficult handling. Therefore, the objective of this work was to carry out the hydrothermal carbonization of rice husk to produce hydrochar as a biofuel using different reaction conditions. The hydrothermal carbonization of the rice husk was performed in a 1 L stainless steel reactor, model CF-1, using temperatures of 180, 190, and 200 °C and reaction times of 1, 2, and 3 h, respectively. The rice husk and the hydrochars were analyzed for pH, moisture content, total solids, volatile solids, ash content, electrical conductivity, elemental analysis, and higher heating value (HHV). The main results showed that the hydrochars had acidic pH values, moisture content below 10%, TS and VS values above 90% and 74%, respectively, high ash content and electrical conductivity, and HHV values greater than 15 MJ/kg. The thermochemical conversion of rice husks helps reduce the volume of a difficult-to-manage agro-industrial waste product and, in turn, provides a biofuel with a higher HHV than the initial biomass (14.34 MJ/kg). At the end of the study, it was observed that one hour was sufficient to improve the HHV compared to uncarbonized rice husks, due to the increase in C (> 38%) and low moisture (< 8%).