This study focused on the characterization and determination of the antibacterial potential of the chitosan extracted from green mussel shells using microwave irradiation. Results showed that chitosan was successfully extracted from green mussel shells yielding a moisture content of 4% and a percentage yield of 1.92%. The result of FTIR analysis revealed different functional groups of organic compounds such as hydroxyl- (3637.17 cm-1 and 3324.31 cm-1), amide- (1652.22 cm-1), alkane/ether- (1026.24 cm-1 and 963.82 cm-1), and carbonate-containing compounds (2517.85 cm-1, 1798.47 cm-1, 1405.89 cm-1, 871.51 cm-1 and 711.65 cm-1). Analysis from FT-IR spectroscopy revealed the Degree of Deacetylation (DDA) as 64.36%, making it suitable for biomedical applications. This study showed that the chitosan samples extracted from the green mussel shells showed antibacterial potential against E. coli and S. aureus. While the chitosan treatments were not as potent as the antibiotic Ciprofloxacin and did not differ significantly from each other, they demonstrated greater inhibition compared to the negative control. Therefore, further comprehensive investigation could establish green mussel shell chitosan as a valuable natural source of antibacterial agents.