Research of sustainability biofuel production methods has accelerated due to the world’s transition to renewable energy. This study explores the possibility of co- pyrolysis plastic waste and algae, two abundant yet environmentally problematic materials to produce biofuel. The combination of plastic trash as an energy-rich co-feedstock and algae’s high lipid and protein content makes them ideal for thermochemical conversion. In this study, several experimental case studies involving different algae species including Nannochloropsis sp, Ulva intestinalis, Ulva lactuca, and Chlorella vulgaris co-processed with synthetic polymers including LDPE, PET, and HDPE are analyzed and contrasted. The impact of operating parameters, including reactor type, temperature, catalyst use, and the particles size, the resultant bio-oil in the yield and energy content is systematically examined in this study. According to the results, the fixed-bed reactor in Case Study 1 produced the most bio-oil (approximately 82 wt%) at 600 °C and 30 min for reaction, although microwave-assisted systems provided benefits in terms of energy content and bio-oil quality. Catalysts like silicon carbide and activated carbon improved conversion and increased thermal efficiency. Additionally, greater heating values of the generated oils varied among the investigations, Case Study 4 achieved 35.23 MJ/kg, whereas Case Study 2 (microwave vacuum reactor) had the highest value (36.6 MJ/kg). The technologies used for condensation, which included solvent wash and ice-water, also contributed to the recovery and purity of the final product. The study evaluates yield and energy output while also emphasizing the environmental significance of turning waste into energy and proving that the co-pyrolysis method is a significant step in decreasing waste accumulation and lowering reliance on fossil fuels. The potential of algae–plastic co-pyrolysis in creating a sustainable, circular bioeconomy is further supported by this study.