This paper contributes to discussions on humanitarian advocacy. The European migration regime as constituted by the Dublin regulation, the EU-Turkey deal and border deals with Libya among others, contributes to generating migration pressure points where migrants find themselves stuck and in desperate need of humanitarian assistance. Assistance and protection at these sites, inasmuch as they are available, are provided by a makeshift humanitarian arena of volunteer organizations, activists, national social welfare agencies, human rights organizations, international humanitarian organizations and UN agencies. Drawing on interviews and field research, this article analyses the relations between, and advocacy practices of, various actors within humanitarian arenas in three settings: Calais (France), Lesbos (Greece) and Libya. The article reveals how many humanitarians at these pressure points feel disempowered in the scope of their action beyond the provision of limited services, and abandoned by established agencies, especially the UNHCR. They feel that humanitarian principles are not enough to guide their actions in these cases. Emerging advocacy practices at these sites suggest that web-based humanitarian advocacy based on actor complementarity may be a way forward, making advocacy more effective and contributing to better motivate aid workers who feel disempowered in these contexts.