Progress on regional cooperation in Southeast Asia is often punctuated by decades rather than years. The exposure of the wider Asia-Pacific to natural hazards renders it the world’s most disaster prone. Since the Indian Ocean earthquake and tsunami in 2004, there have been three significant broad trends that have shaped humanitarian diplomacy, namely ASEAN as a platform for engagement, sectoral approaches and a diversifying multi-stakeholder environment creating a multi-level regionalism in Southeast Asia. States and societies in Southeast Asia have demonstrated a commitment to building humanitarian capacity which is often termed ‘nationally led, regionally supported and international as necessary’ so that they can lead response to natural hazards. The experience of natural hazards offers an important reference for humanitarian work in other areas, notably health emergencies and conflict settings. However, the localization of the global humanitarian system beyond the regional and national levels to local communities remains far from certain, and progress made in this arena may yet come undone without sustained and substantive political commitment from ASEAN member states.