The submarine arms race in the Indo-Pacific region that has been underway for almost 10 years is continuing apace as more navies are expanding their fleets and are bringing new boats into service. Dr Collin Koh Swee Lean, from tRSIS said that while the increase in the size and sophistication of China’s People’s Liberation Army Navy (PLAN) “does play a significant role spurring the equivalent build-ups by at least some regional countries, such as Japan, there are a few other drivers.”