Bacterial communities collaborating with seaweed play an important role in many aspects, especially in the production of secondary metabolites that help ecosystem function and have good prospects for pharmacological utilization. The objective of this study was to determine the antibacterial activity of associated bacteria isolated from seaweed in Awur Bay, Jepara, Indonesia. The antibacterial test uses the pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, and Micrococcus luteus. Isolation of seaweed-associated bacteria obtained 4 potential isolates, which were closely related to Vibrionaceae bacterium PH25 (99.86%), Vibrio alginolyticus strain GS MYPK1 (99.65%), Salinivibrio costicola strain M318 (99.86%), and Vibrio alginolyticus strain 2014V-1011 (99.93%). In disc diffusion, MIC, and MBC tests, four isolates showed potential antibacterial activity. TLC identified groups of compounds that were reported to have antibacterial activity, such as alkaloids, terpenoids, steroids, and flavonoids. Compounds that were reported to have antibacterial properties were identified from GCMS, one of which was the compound azulane (CAS).