The Marine Geoscience Data System (MGDS) is a trusted data repository that provides free public access to a curated collection of marine geophysical data products and complementary data related to understanding the formation and evolution of the seafloor and sub-seafloor. Developed and operated by domain scientists and technical specialists with deep knowledge about the creation, analysis and scientific interpretation of marine geoscience data, the system makes available a digital library of data files described by a rich curated metadata catalog. MGDS provides tools and services for the discovery and download of data collected throughout the global oceans. Primary data types are geophysical field data including active source seismic data, potential field, bathymetry, sidescan sonar, near-bottom imagery, other seafloor senor data as well as a diverse array of processed data and interpreted data products (e.g. seismic interpretations, microseismicity catalogs, geologic maps and interpretations, photomosaics and visualizations). Our data resources support scientists working broadly on solid earth science problems ranging from mid-ocean ridge, subduction zone and hotspot processes, to geohazards, continental margin evolution, sediment transport at glaciated and unglaciated margins.