The tri-border area (TBA) between the Philippines, Malaysia, and Indonesia is a key hub of terrorist and related criminal activity in Southeast Asia. The authors analyze the security environment in the region, examine the Philippines' Coast Watch System, and consider the prospects for forming an integrated system of maritime security that would tie together the three states that converge in the TBA. Analyzes the security environment in the tri-border area between the Philippines, Malaysia, and Indonesia and considers ways to improve maritime domain awareness in the region. Analyzes the security environment in the tri-border area between the Philippines, Malaysia, and Indonesia and considers ways to improve maritime domain awareness in the region.