Current concern over the decrease in the use of fossil fuels has led to the study of various options as an alternative to replace them in the transportation and industrial sectors. Different materials, such as agricultural products, lignocellulosic residues, solid wastewater products, and algae, can be used in the production of biochar and, through a sulfonation process, it can be converted it into a heterogeneous acid catalyst. The purpose of this study was employed coconut mesocarp as lignocellulosic biomass feedstock, obtaining sulfonated biochar (BACS), and evaluates its use in biodiesel production, comparing it with a KOH catalyst. The methodology included the pyrolysis of coconut mesocarp and the activation with H2SO4 for BACS production. BACS was characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, BET surface area analysis and elemental analysis. The biodiesel obtained by BACS and biodiesel obtained by KOH were compared using international biodiesel standards. An activated sulfonated biochar with a sulfonation percentage of 15.23% was successfully obtained, providing a higher FAME conversion percentage than the KOH catalyst. During the characterization of the biodiesel obtained with both catalysts, it was found that KOH meets the specified standards, while the BACS catalyst requires variations in reaction temperature or blending with diesel to comply with the biodiesel characteristics. Additionally, it was observed that the coconut mesocarp-based catalyst showed a 2.78% reduction after the first working cycle, allowing for its reuse without the need for a new sulfonation process.