The escalating environmental concerns regarding plastic waste necessitate innovative strategies for waste management and resource utilization. This study presented a novel approach for synthesizing high surface area activated carbon through a single-step process, using polyethylene terephthalate (PET) plastic waste as the precursor and potassium hydroxide (KOH) as the activating agent. The optimal activation conditions were established using a weight ratio of 1:1 of PET to KOH and annealing for 15 minutes at 700 oC. The conversion efficiency of PET plastic trash into activated carbon exceeded 20%. The materials underwent thorough characterization using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR). The activated carbon obtained has a mesoporous structure and a surface area of 1831.166 m2/g. The activated carbon-prepared plastic waste showed high removal efficiency for the organic dyes in an aqueous solution, with a maximum adsorption capacity of 131.58 mg/g. The successful transformation of plastic waste into a valuable resource underscores the importance of innovative approaches to mitigating environmental degradation. The synthesized activated carbon's efficacy in adsorption-based remediation strategies establishes its potential for addressing various pollution issues and opens new avenues for valuing plastic waste.