This paper explores the history of radio echo-sounding (RES), a technique of glaciological surveying that from the late 1960s has been used to examine Antarctica's sub-glacial morphology. Although the origins of RES can be traced back to two accidental findings, its development relied upon the establishment of new geopolitical conditions, which in the 1960s typified Antarctica as a continent devoted to scientific exploration. These conditions extended the influence of prominent glaciologists promoting RES and helped them gather sufficient support to test its efficiency. The organization and implementation of a large-scale research programme of RES in Antarctica followed these developments. The paper also examines the deployment of RES in Antarctic explorations, showing that its completion depended on the availability of technological systems of which RES was an integral part.