Defence diplomacy is an increasingly important tool for strategic engagement used by states in Southeast Asia. This approach underpins simultaneous cooperation and competition in the contemporary Indo-Pacific region amid major power rivalries and growing activity in Southeast Asia and the South China Sea.

The rise of China and the intensifying Sino–US competition has caught Southeast Asia at a geostrategic pivot where smaller states' strategic autonomy is increasingly difficult to manage. To address uncertainty in contemporary international relations, Southeast Asian states tend to hedge omnidirectionally. This helps them to avoid entrapment, abandonment, and over-dependence on any one major power. Such an adaptive combination of bilateral, multilateral, and minilateral defence diplomacy and security cooperation allows these states to diversify their relations with several bigger powers, avoiding direct involvement of outside powers in Southeast Asian affairs while delaying having to choose sides between China and the United States.

This is the first book-length coverage of defence diplomacy in Southeast Asia and an important update on previous studies. It bridges a gap in the literature by linking defence diplomacy to a broader theoretical framework of alignment behaviour, and offers much-needed look into smaller powers' manoeuvring between major powers. This volume will be of interest to academics and policymakers alike, providing fresh perspectives and ideas for civilian and military decisionmakers and practitioners. More broadly, it will attract those seeking to better understand the military's role in foreign and security policy.