This dataset contains monthly and annual means of ocean and sea ice variables from a 30 year (1976-2005) integration of the GOSI9 model configuration at 1/12° horizontal resolution. The ocean output fields on T, U, V, and W grids are provided in separate files. The ocean component is on a 1/12° grid (eORCA12) with 75 vertical levels. The sea ice data is on the ocean T grid with 5 thickness categories. GOSI9 is the latest version of the global ocean-sea ice configuration developed under the Joint Marine Modelling Programme (JMMP). The temperature and salinity fields were initialised from EN4 climatology (Good et al., 2013) and forced by the CORE2 surface dataset (Large & Yeager, 2009). All initialisation and ancillary data are also included. The data were generated under the Climate Linked Atlantic Sector Science (CLASS) project funded by the Natural Environment Research Council (NERC).