Since 2010, pelagic Sargassum spp. blooms have increased in several tropical Atlantic regions, causing socioeconomic and ecosystem impacts. Offshore structuration of Sargassum by mesoscale dynamics may influence transport and growth. Sargassum stays afloat, constantly interacting with currents, waves, winds, and mesoscale eddies. We find that anticyclones and cyclones effectively trap Sargassum throughout its propagation, with a greater tendency for cyclones to accumulate Sargassum.