Australia has deployed two ships to waters off Guam in the Pacific to join military exercises with the US, Japan and South Korea.
Exercise Pacific Vanguard will involve eight ships from the four nations and more than 1500 personnel.
Defence Minister Linda Reynolds said the exercise would bring together key and like-minded regional partners, working in support of a shared vision for a secure, open, prosperous and inclusive region.
"The increasing complexity of our security environment highlights the importance of maintaining and growing our regional partnerships," Senator Reynolds said.
"Ours is a strong community built on shared interests, and activities like Exercise Pacific Vanguard increase our ability to contribute to the peace and stability of the Indo-Pacific."
The Australian navy's Anzac Class frigates Stuart and Arunta will take part in the exercises which include combined manoeuvres, surface warfare, live-fire exercises, anti-submarine warfare and replenishment at sea operations.
Japanese ships Ashigara and Ise, Korean ships Chungmugong Yi Sun-sin and Seoae Ryu Seong-ryong, the USS Barry, and the US supply ship John Erickson will also take part.
Commander of the Australian Maritime Task Group, Captain Phillipa Hay said it was more important than ever for Australia to increase practical cooperation with its regional partners.
"Pacific Vanguard is an invaluable opportunity to increase the Royal Australian Navy's understanding and experience working with the Japan Maritime Self-Defence Force, Republic of Korea Navy and United States Navy," she said.