Regional security is becoming an increasingly important for Southeast Asia, this is due to the economic and political milestones amassed by the region over the decades as well as the heating rivalry within the Indo Pacific. Being the most influential state in the region, Indonesia’s efforts in fostering to Southeast Asian regional security through BAKAMLA and TNI-AL deserves closer examination. By extension, its ability to maintain its sovereignty will be inspected as well. This thesis seeks to find out what were the significance of Indonesia’s efforts to Southeast Asian regional Security along with the challenges faced by Indonesia it is effort in doing so. Neorealist theory, security and sovereignty concepts, qualitative approach and descriptive methods will be utilized for analysis. The significance of this thesis’s findings is that Indonesia’s efforts in fostering regional security and maintaining sovereignty reinforces its de facto leadership in the region along its credibility within the international community. Furthermore, the identified challenges to regional security can serve as wake-up call to policy makers to take the matter more seriously given the severity of the issue.