The European Centers for Medium range Weather Forecasts (EMCW) Ocean Re-Analysis System 3(ORA-S3) datasets, created by the synthesis of surface and subsurface ocean observations (temperature, salinity, altimeter derived sea-level anomalies) , surface fluxes from atmospheric analysis and reanalysis, and a general circulation ocean model(HOPE). ORA-S3 was created and is used to provide initial conditions for coupled model forecasts as well as seasonal & decadal forecasting predictions within the ENSEMBLES project. The CSIRO version of the ORA-S3 dataset is a concatenation of the individual monthly variables into single netcdf files for the time period 1959-2006 at 256 lat & 195 Lon positions with 29 Levels. It has also been processed to include calculated Anomaly, Climatological and Seasonal forms of this data. There are 10 Monthly files 13.0GB, 10 Anomaly files 13.0GB, 10 Climatology files 557MB, and 10 Seasonal files 9.81GB.