In 2005 Geoscience Australia and the National Oceans Office undertook a joint project to produce a consistent, high-quality 9 arc second (0.0025° or ~250m at the equator) bathymetric grid for Australian waters. In 2009 a number of new datasets were included in an updated version of the grid. The 2009 bathymetric grid of Australia has been produced to include recently acquired datasets, and solutions to issues identified in the previous version. The revised grid has the same extents as its 2005 counterpart, including the Australian water column jurisdiction lying between 92° E and 172° E, and 8° S and 60° S. The waters adjacent to the continent of Australia and Tasmania are included, as are areas surrounding Macquarie Island, and the Australian Territories of Norfolk Island, Christmas Island, and Cocos (Keeling) Islands. The area selected does not include Australia's marine jurisdiction offshore from the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. This report details the datasets and procedures used to produce the 2009 bathymetric grid of Australia. As per the 2005 grid, the 0.0025 decimal degree (dd) resolution is only supported where direct bathymetric observations are sufficiently dense (e.g. where swath bathymetry data or digitised chart data exist) (Webster and Petkovic, 2005). In areas where no sounding data are available (in waters off the Australian shelf), the grid is based on the 2 arc minute ETOPO (Smith and Sandwell, 1997) and 1 arc minute ETOPO (Amante and Eakins, 2008) satellite derived bathymetry. The topographic data (on shore data) is based on the revised Australian 0.0025dd topography grid (Geoscience Australia, 2008), the 0.0025dd NZ topography grid (Geographx, 2008) and the 90m SRTM DEM (Jarvis et al, 2008). The final dataset has been provided in ESRI grid and ER Mapper (ers) formats. An associated shapefile has been produced so that the user can identify the input datasets that were used in the final grid. IMPORTANT INFORMATION This grid is not suitable for use as an aid to navigation, or to replace any products produced by the Australian Hydrographic Service. Geoscience Australia produces the 0.0025dd bathymetric grid of Australia specifically to provide regional and local broad scale context for scientific and industry projects, and public education. The 0.0025dd grid size is, in many regions of this grid, far in excess of the optimal grid size for some of the input data used. On parts of the continental shelf it may be possible to produce grids at higher resolution, especially where LADS or multibeam surveys exist. However these surveys typically only cover small areas and hence do not warrant the production a regional scale grid at less than 0.0025dd. There are a number of bathymetric datasets that have not been included in this grid for various reasons. Comments or queries about the data included in the grid (or excluded) can be directed to: IDEASRequests@ga.gov.au. This grid is not suitable for use as an aid to navigation, or to replace any products produced by the Australian Hydrographic Service.