This study investigated the prevalence, serotypes, antimicrobial resistance, virulence genes, and biofilm-forming ability of Listeria monocytogenes isolated from raw chicken meat in Japan in 2022 and compared the findings with isolates collected in 2012 and 2017. Among 85 chicken samples, 10.6% were positive for L. monocytogenes, representing a significant decline from 24.0% in 2017 and 52.9% in 2012. The proportion of multidrug-resistant isolates also decreased to 16.7%, although resistance to cefoxitin, oxacillin, and fosfomycin remained common. Most isolates carried the major virulence genes (hlyA, plcA, clpC, and inlA), while the 2022 isolates exhibited significantly weaker biofilm formation than those from previous years, suggesting reduced pathogenic potential. The study concludes that although contamination levels and antimicrobial resistance have decreased, pathogenic L. monocytogenes remains a food safety concern in Japan. Additionally, MALDI-TOF MS proved to be a valuable tool for epidemiological characterization of L. monocytogenes isolates.