The demilitarisation provisions of the 1959 Antarctic Treaty are limited and contingent. Critically, a functional gap is enabled within the key Article I, which both prohibits ‘measures of a military nature’ and sanctions the use of military personnel and equipment in pursuit of ‘peaceful purposes’. None of the key terms and concepts are defined. With increasing focus on and in the Antarctic Treaty Area on interstate competition around resource access and regime control, and in particular the rapidly increasing geopolitical struggle between ‘the West’ and China both globally and within the Antarctic, and the transformation of what military activity actually entails, the existing demilitarisation principles are now inadequate. The failure to update these in the 60 years since the Antarctic Treaty was adopted, the lack of confidence that the historic Antarctic Treaty model of regional governance can itself manage the struggle, and indications over recent years that some states are even increasing the level of military entanglement with their Antarctic programmes, suggest it is now timely to reassess and respond to the case for substantive demilitarisation in the Antarctic Treaty Area.