Little is known about the ecological relationship of Vibrio bacteria with Sargassum. Evidence also is sparse as to whether vibrios colonizing plastic marine debris and Sargassum could potentially infect humans. As summer kicks off and efforts are underway to find solutions to repurpose Sargassum, could these substrates pose a triple threat to public health? Results of a study representing the first Vibrio spp. genome assembled from plastic finds Vibrio pathogens have the unique ability to stick to microplastics, harboring potent opportunistic pathogens.