This data is a combination of records held by the Australian Maritime Safety Authority. From 1999 to 2011 Australia shipping was tracked through the Australian Ship Reporting System (AUSREP). From 2012 onward this changed to the Automatic Identification System (AIS). The data presented here are summaries of the tracks of vessels between the points identified by either AUSREP or AIS, summarised to the number of KM per 0.1 deg grid square. The AIS is a Very High Frequency (VHF) radio broadcasting system which enables AIS equipped vessels and shore-based stations to send and receive identifying information. This information can: be displayed on a computer or chart plotter aid in situational awareness provide a means to assist in collision avoidance. The International Maritime Organization (IMO) defines AIS as a ship and shore based broadcast system, operating in the VHF maritime band. The AIS can handle over 2,000 reports per minute and may update information as often as every two seconds. https://www.amsa.gov.au/navigation/services/ais/ Australian Ship Reporting System (AUSREP) is a ship reporting system designed to contribute to the safety of life at sea and is operated by the Australian Maritime Safety Authority (AMSA) through the Australian Rescue Coordination Centre (RCC Australia) in Canberra. Participation in AUSREP is mandatory for certain ships but most other commercial ships participate voluntarily. Shipmasters send a position report each day at a convenient time nominated by the ship, the maximum time between any two reports is not to exceed 24 hours. The data is used as reference material only, designed to indicate shipping lanes and the number of vessels moving through Australian waters. AUSREP commenced in 1973 in line with Australia's obligations under the International Convention for the Safety of Life at Sea (SOLAS) as a ship reporting system and is operated by AMSA through the RCC Australia in Canberra. https://www.operations.amsa.gov.au/Spatial/DataServices/MapProduct