Southeast Asian nations have long understood that effective national security goes well beyond military preparedness to encompass a variety of ‘non-traditional’ security issues. This idea is at the heart of political cooperation within ASEAN and competes with traditional notions of regional security in East Asia. But the vocabulary that has developed in the face of growing geopolitical tensions—decoupling, dual circulation, friendshoring, ‘strategic’ supply chains, securitisation—suggests that the big powers are working towards their own notion of comprehensive security. Contributors in this issue recognise that comprehensive regional security can only be secured collectively: one country’s resilience to climate change or access to free and well-served markets for energy and food doesn’t come at the expense of others. This issue of East Asia Forum Quarterly explores the idea of comprehensive regional security—an approach that embraces economic, environmental and energy security as well as military interests and considers how they are secured within today’s economically interdependent and politically cooperative regional system.