The paper concerns the application of public diplomacy measures to preserve border security of Australia, which nowadays is the key interest of this state. First, the meaning of public diplomacy in Australia is analysed, and next, the notion of border security of Australia – in a broader context of its national, homeland and internal security – is elaborated upon. The main argument is that in the case of Australia public diplomacy is inseparably linked with its security and it is used as one of the means of preserving Australia’s territorial integrity. Border security is therefore an essential national interest of the state and public diplomacy would be applied as a tool to ensure it. The key research questions posed in this article concern the nature of public diplomacy and border security of Australia, the relationship between the two notions in the case of Australia, and the ways in which public diplomacy can be used to pursue border security goals. The analysed period covers the years 2006–2015. First, in 2006 and 2007 there emerged a public debate on the further directions of Australian overseas activities, provoked by the 2006 Australian Senate inquiry on the nature and ways of conducting Australia’s public diplomacy. Second, in 2013–2015 border security and migration policy became hot topics for Australian politicians due to the rapidly increasing number of unauthorised arrivals on boats as well as institutional changes in the service responsible for border security. Between 2006 and 2015 Australian federal authorities adopted the most crucial documents both on public diplomacy and national security (which is linked with border security issues), and during this period Australia carried out the “Stopping the Boats” campaign focused on eliminating unauthorised arrivals to its territory by boat.