This chapter examines the extent to which a reordering of security boundaries is either desirable or possible in East Asia. Scholarship on regionalism in East Asia has begun to engage with the changing profile of security agenda. The ASEAN Regional Forum (ARF) tends to be cited as the only security arrangement in the Asia-Pacific. However, ASEAN Plus Three (APT) cooperation began in December 1997 when leaders of ASEAN joined an informal summit with their counterparts from Japan, China and the Republic of Korea. By addressing the nature of comprehensive security within East Asia, the chapter also examines some of the tensions inherent within East Asian concepts of security. By considering the concept of human security, it explores the possibilities and constraints for the emergence of more normatively progressive sets of security discourses and practices, and of space for a range of critical actors.