Particle tracking model output simulating floating marine litter in the Bay of Bengal, 2018 to 2019 dataset https://portal.medin.org.uk/portal/start.php?tpc=009_CEFASee9b441a-b04d-4013-92fe-56f5eab85b2f These data are particle positions and dates/times which are output from an OceanParcels particle tracking model simulating likely pathways of floating marine macro-litter in the Bay of Bengal between 1st June 208 – 30th September 2019, saved as NetCDF files. The model incorporated advection due to ocean, wind, and Stokes drift velocities, horizontal diffusion, and particle beaching behaviours. Two different hydrodynamic data sets were used to force the particles’ trajectories: a high-resolution ocean velocity hindcast (ROMS – Regional Oceanic Modelling System) and a lower-resolution dataset which included data assimilation (CMEMS - Copernicus Marine Environment Monitoring Service). Sensitivity tests were run to determine whether hourly or daily forcing resulted in significantly different particle end locations and validation simulations were run to compare with undrogued drifter tracks for the same period and region. All model output is stored in NetCDF files. This is data to accompany a manuscript submitted to Ocean Science entitled ‘Monsoonal influence on floating marine litter pathways in the Bay of Bengal’ (Preprint: `EGUsphere - Monsoonal influence on floating marine litter pathways in the Bay of Bengal`_). These experiments aimed to determine source-to-sink connectivity between countries surrounding the Bay of Bengal. .. _`egusphere - monsoonal influence on floating marine litter pathways in the bay of bengal`: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-3096/ 20241002 20240925