Australia, the Philippines, and the United States have conducted a multilateral Maritime Cooperative Activity (MCA) within the Philippines’ Exclusive Economic Zone, reinforcing trilateral defence cooperation in the Indo-Pacific region.

The MCA was carried out on February 15–16, 2026, and featured the Royal Australian Navy’s Anzac-class frigate HMAS Toowoomba, supported by a Royal Australian Air Force P-8A Poseidon maritime patrol aircraft. The activity also involved the Philippine Navy vessel BRP Diego Silang with its embarked AW109 helicopter, Philippine Air Force FA-50PH and A-29 Super Tucano aircraft, and the Philippine Coast Guard patrol vessel BRP Teresa Magbanua. The United States Navy participated with the destroyer USS Dewey, along with a P-8A Poseidon aircraft.

Australia said its participation underscores a strong commitment to regional and international cooperation in support of a peaceful, stable, and prosperous Indo-Pacific. The MCA demonstrated the partners’ ability to uphold international law, including freedom of navigation and overflight, in line with the United Nations Convention on the Law of the Sea. Australia also reaffirmed that the 2016 South China Sea Arbitral Tribunal Award is final and legally binding.

Strong cooperation through such activities enhances interoperability and readiness to respond to shared security challenges. HMAS Toowoomba is currently on a Regional Presence Deployment, reflecting Australia’s ongoing commitment to maintaining a near-continuous presence to support regional security and stability.