Antarctica is arguably the only geographical territory left on Earth without political borders. Narratives of peace, science and environmental protection in the Antarctic Treaty System drive a collective governance system that avoids border discourse even though physical boundaries exist. This article fills a gap in Antarctic research by exploring the question ‘What borderwork is evident in the Antarctic Treaty System in relation to the construction and maintenance of its physical boundaries?’ through a study of a gateway to Antarctica—New Zealand. Borderscaping and borderwork concepts are used to examine territoriality in Antarctica. Enacted narrative analysis reveals effects of strategic narrative on practices, showing the Antarctic Treaty system has created an ‘implied’ border system that lacks some of the capabilities of an acknowledged border system. The article argues that understanding the full reach of the absences on practices and attitudes in this Antarctic system is important for the continent’s ongoing security and for border theory. It concludes that more needs to be known about the subtle effects on the many actors in this implied borderscape. Such further research will add to knowledge about Antarctic practices and governance and borderscaping theory.