Since 2011, substantial amounts of pelagic Sargassum algae wash-up along the Caribbean beaches and the Gulf of Mexico, hence leading to negative impacts into the economy and the environment of those areas. Hence, it is now crucial to develop strategies to mitigate this problem while valorizing such invasive biomass. This work deals with the successful exploitation of this pelagic Sargassum seaweed for the fabrication of carbon materials that can be used as electrodes for supercapacitors (Marie-Julie Pintor, 2013);(Encamacion Raymoundo-Pinero, 2009). A pelagic Sargassum spp precursor was simply pyrolysed at temperature varying from 600 to 900°C. Activated carbons were also prepared from sargassum natans by hydrothermal carbonization (HTC) pretreatment at 200°C during 24hours and chemically activated with KOH. The resultant carbonaceous materials were then extensively characterized using different techniques, such as nitrogen adsorption for textural characterization, as well as, X-ray photoelectron, Fourier transform infrared spectroscopies and Scanning Electron Microscopy, to understand their structures and functionalities. The electrochemical properties of the carbon materials were also tested for their performance as supercapacitors using cyclic voltammetry, galvanostatic method and electrochemical impedance spectroscopy analyses. References : E. Raymoundo-Pinero, M. Cadek, and F. Béguin Tuning Carbon Materials for Supercapacitors by Direct Pyrolysis of Seaweeds , Avanced Functional Materials. - 2009. - pp. 1032-1039. M.-J. Pintor, C. Jean-Marius , V. Jeanne-Rose , P-L Taberna , P. Simon , J. Gamby C, R. Gadiou , S. Gaspard Preparation of activated carbon from Turbinaria turbinata seaweeds and its use as supercapacitor electrode materials, CR Chimie. - 2013. - pp. 88-99.