The Rim of the Pacific (RIMPAC), which runs every two years off the coast of Hawaii, has included more than 430 Australia Defence Force personnel, two aircraft, and two vessels.
This year, it was also accompanied by Fiji, which joined RIMPAC for the first time in 2026, shortly before signing a historic defence deal with Australia in early July.
The deal, and Fiji's RIMPAC participation, advanced the federal government's strategy to limit China's influence across the Pacific region.
Hours after the arrangement was signed, China launched a long-range nuclear missile test in the South Pacific.
Tonga joined RIMPAC in 2018, while Australia and New Zealand have been part of the operation since its inception in 1971.
United States Vice Admiral Jeffrey Jablon told reporters on Wednesday RIMPAC was not just about signalling to a specific nation, and instead focused on the "readiness of all the participating nations".
But for Australia, having the involvement of Pacific islands is an important step to shoring up the nation's influence in the region.
The country fired a naval strike missile from HMAS Sydney as part of the exercise; just the second time the navy has done so at RIMPAC.
Critics of the exercise have said Australia's participation puts it in position to join further US-initiated conflict.
"We are not facing any threat to regional stability and security from China, our major trading partner," Alison Broinowski of the Independent and Peaceful Australia Network said in a statement.
"Rather, it is the ongoing US and Australian provocations in the South China Sea that represent the real danger."
The comments come after the US allocated $US30 million in June to stockpile war-ready equipment for its marine corps in Bandiana, near Wodonga.
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