In recent years there have been repeated calls for the establishment of so-called “safe areas” to protect civilians from the effects of hostilities in a number of contexts. The present article presents the international law framework relevant to the establishment and operation of such areas: the provisions of international humanitarian law on protected zones; the rules regulating resort to armed force, Security Council authorization and mandates for the establishment of such areas by multinational forces in the absence of agreement between belligerents; and the refugee and international human rights issues raised by such zones. Using the example of the “protection of civilians sites” in South Sudan, the article then highlights some of the operational challenges raised by safe areas. It concludes with some reflections on how to enhance the likelihood that belligerents will establish such protected zones in the future.