Microplastic contamination and antimicrobial resistance (AMR) represent emerging concerns in marine ecosystems and seafood safety. This study assessed the presence of microplastics, bacterial isolates, and their antimicrobial susceptibility profiles in Decapterus macrosoma (galunggong) collected from Cavite, Philippines. A total of 100 fish were dissected, and stomach contents were processed using potassium hydroxide digestion and wet peroxide oxidation to isolate microplastics. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK® 2 system, with MIC interpretation based on CLSI M100 (2024) standards. Microplastics were detected in 94% of samples, with individual fish containing between 0 and 4 particles, predominantly fibers. Bacterial isolates were dominated by members of the Enterobacteriaceae, including Klebsiella pneumoniae, Escherichia coli, Raoultella ornithinolytica, and Citrobacter freundii, along with additional isolates such as Enterobacter cloacae, Proteus mirabilis, Proteus penneri, Aeromonas spp., Pseudomonas aeruginosa, and Sphingomonas paucimobilis. Antimicrobial susceptibility patterns showed high sensitivity to carbapenems, aminoglycosides, ciprofloxacin, and cefepime, with resistance observed to ampicillin, cefuroxime, cefuroxime axetil, cefoxitin, and colistin + polymyxin B. Pearson correlation tests revealed no significant relationship between microplastic count and the number of resistant antibiotics, and Fisher’s Exact Test indicated no significant association between microplastic presence and the occurrence of resistant bacteria. These findings provide baseline data on microplastic ingestion and bacterial resistance profiles in D. macrosoma while demonstrating no measurable association between microplastic load and AMR under the study conditions.