Accumulation of marine plastic debris is an emerging and worsening man-made problem. It is not only becoming an ecological threat to marine animals but could also facilitate the dispersal of harmful algal bloom-causing microorganisms (HABs). These dangerous hitchhikers remain viable and could serve as propagules for invading new territories. However, despite the high prevalence of HABs in the country, no studies have been done to look at the possibility of plastics to transport these harmful species. In general, the project aims to establish baseline data on the abundance of plastics in selected sampling sites and investigate the presence of dangerous hitchhikers in floating plastics. This will generate novel insights on how plastics could serve as carriers to hitchhiking HABs species and further understand the dispersal of HABs within and between coastal systems in the Philippines.