In this study, the successful preparation of activated carbons from Corn Stigmata, either through direct pyrolysis and activation or through a preliminary additional hydrothermal carbonisation (HTC) step, was reported. It was shown that the latter allowed producing higher carbon yield, higher carbon content and higher BET area (A BET) after 2h of activation with CO 2 than what was observed for activated carbons (ACs) prepared in the same conditions but without HTC. The AC having the most developed porous texture, A BET = 1111 m 2 /g, was further investigated by FTIR, SEM and potentiometric titration, and its pH at point of zero charge was determined. Its performances in terms of methylene blue (MB) adsorption were studied and discussed in relation to its textural and chemical characteristics. Due to its very heterogeneous surface, the fractal Brouers-Sotolongo model was the most relevant for describing both kinetic and equilibrium adsorption data. The calculated thermodynamic parameters also showed that MB adsorption was spontaneous on this material. The high MB uptake at room temperature, compared to many other results published in the literature, further confirmed the interest of Corn Stigmata-derived hydrochars as precursors of activated carbons.