Last month, Thailand’s navy requested funding for a submarine program which, when finalized, will make it the region’s eighth submarine-equipped nation—joining Malaysia, Singapore, Indonesia, Vietnam, Taiwan, India, and Australia. The Philippines, Thailand, and Bangladesh, meanwhile, have all expressed interest in acquiring submarine fleets. As tensions in the South China Sea continue to escalate, this arms race poses a significant threat to the security of the region.

The rapid improvement of military capabilities in Southeast Asia has not deterred China, however, which continues to construct man-made islands and runways on partially submerged coral reefs. In response to the naval build-up in the region, Beijing, which boasts the world’s largest submarine fleet, has begun to double down on its anti-submarine warfare (ASW) capabilities.  Take, for instance, the recent addition of the GX-6 anti-submarine aircraft, which will enhance PLA maritime patrols and reconnaissance while expanding China’s ASW capabilities by over six-hundred miles. China is also investing heavily in sea-floor mapping and sonar technology to improve its intelligence and tracking abilities, part of an announced 10.1 percent increase in its 2015 defense spending, bringing its total defense budget to $145 billion dollars.