The Antarctic Treaty marks a fundamental milestone in the handling of Antarctica. This treaty contains some mechanisms that, until now, have been effective in protecting the Antarctic territory. In this article the hows and whys of said mechanisms are laid out. However, at the same time the effectiveness of the mechanisms are only applicable to the states that form part of the Antarctic Treaty. How then would the Antarctic territory be defended with respect to states that are not party to the Antarctic Treaty? The proposed answer to this question consists in confirming that the evolution of the so-called "Question of Antarctica" has generated a custom in international law in such a way that the principles of the Antarctic Treaty are enforceable against third party States that are not party to this treaty.