A series of simulations to test the vulnerability of Australia's ocean access demonstrated maritime trading routes required protection across the full length of the Indian Ocean, not just in waters close to Australia.
A recent matrix game involving nine former senior military and defence officials from Australia, India, the United States and Japan has found that a modest undersea threat against shipping in the central Indian Ocean could severely disrupt trade across the entire region, driving up war-risk insurance premiums, forcing costly route diversions, or pushing commercial traffic out of the ocean altogether.
The findings matter for Australia, which conducts 99% of its global trade by sea. The recent closure of the Strait of Hormuz during the US-Iran war underlined how exposed maritime trade routes can be to disruption.
"Australia has the largest Indian Ocean coastline of any country, yet we often overlook it in our strategic planning," says Professor Bec Strating, Director of the La Trobe Centre for Global Security. "This matrix game showed that a single incident could disrupt trade across the entire Indian Ocean. We can no longer afford to treat this as someone else's ocean."
The multi-day simulation tested how the Australian, US and Indian militaries would respond to two crisis scenarios involving China. It found that protecting Australia's trade routes requires securing the full length of the Indian Ocean, not just the waters closest to the Australian coastline.
The exercises also exposed how dependent Australia's navy is on US support to operate at distance, while showing that closer coordination between partner militaries meaningfully improves operational effectiveness.
"The simulation shows how the threat is intensifying as China's naval presence expands across the Indian Ocean, including its growing undersea capabilities," says Arzan Tarapore, a Research Scholar at Stanford University. "This is a wake-up call about how thin Australia's margin for error really is in the Indian Ocean."
The research forms part of a broader project, Enhancing Military Cooperation on the Indian Ocean, led by researchers from Stanford University, La Trobe University and the Australian National University. Peter Dean, Professor of Strategic Studies at ANU, and Ambika Vishwanath and Hannah Bourke of the La Trobe Centre for Global Security also contributed to the research.
