“Maritime Security” has emerged as a central concept in Southeast Asia’s policy lexicon. However, as is the case in much of the world, the term’s precise meaning is not consistently clear. Which challenges and state activities should be categorised as maritime security and which should be considered elements of another domain is generally ambiguous. This ambiguity can be useful to leaders seeking to build unity of action among government agencies with overlapping maritime policy mandates and to diplomats seeking to rely on euphemisms to support flexible political narratives that minimise the risks associated with security dilemmas.  However, such linguistic polysemy only works for so long and introduces risk. Left unclarified, terms will develop assumed meanings. For example, many Southeast Asians regard contemporary American talk about maritime security as a thin veil for something better understood as “great power competition at sea”. Therefore, even the most benign initiatives are factored into regional calculations aimed at balancing between external powers. Within the region, it is also possible for lexical disconnects to lead to problematic misinterpretations of policy intent and diplomatic signals.

Recognising that understanding varied conceptional definitions of maritime security is an academic puzzle with real-world practical implications in Southeast Asia, RSIS convened a roundtable of experts on 21 September 2021 to take stock of regional maritime security definitions. These specialists surveyed national policy documents and policymaker discourses to assess how maritime security is defined, used and conceptualised in seven key Southeast Asian coastal states (the Philippines, Vietnam, Brunei, Malaysia, Indonesia, Singapore and Thailand), in ASEAN as a multinational institution, and within member states of the Quad (Australia, Japan, India and the United States). This stocktaking enabled the experts to identify and discuss the significance of the convergences and divergences between the various conceptions of maritime security. While the primary goal of the project was to improve communication by providing a common reference point, the project also uncovered findings of practical policy importance.