Ushuaia and Punta Arenas are the southernmost cities in their belonging countries, Argentina and Chile. They have played the role of frontier towns in the process of consolidation and legitimation of these austral national territories located in the periphery of South America. During the last fifty years, these two port cities have emerged as the two main international gateways to Antárctica, and especially to Antarctic Peninsula. They participate in the structuring of a multifaceted Antarctic frontier conquest: military, scientific, ecological and tourism. The bridgehead is a key concept to rethink the territorial structuring and control of conquest frontier. If we recall proximity and connection as minimal criteria to define a gateway, political control and territorial reference tend to reinforce the gateway as the main bridgehead place of the conquest frontier. Are then Ushuaia and Punta Arenas becoming Antarctic-driven cities? How are they used in the antartic national policies of Argentina and Chile?