Australian, Philippine and US naval forces sail together during a multilateral MCA in the Philippine EEZ from August 19 to 25. (Facebook/Armed Forces of the Philippines)
Australia, the Philippines and US conducted a seven-day Maritime Cooperative Activity (MCA) within the Philippines’ Exclusive Economic Zone (EEZ) in South China Sea from August 19 to 25.
The activity involved naval, air and coastguard units from the three countries and included maritime domain awareness, communications exercises, replenishment at sea, search and rescue, tactical manoeuvres and fly-by operations.
The Philippines deployed the BRP Diego Silang frigate with an embarked AW109 helicopter, FA-50PH and A-29B aircraft, the Philippine Coast Guard’s BRP Teresa Magbanua, as well as C-208B and W-3A Sokol aircraft. The US contributed the USS Santa Barbara littoral combat ship and a P-8A Poseidon maritime patrol aircraft. Australia deployed the HMAS Supply, a Supply-class auxiliary oiler replenishment vessel, with an embarked MH-60R Seahawk helicopter, supported by a Royal Australian Air Force P-8A Poseidon.
The cooperative activity was the 19th multilateral maritime cooperative activity conducted by the Philippines with the two partners since the series began in April 2024. The US Navy separately identified it as the 10th MCA of 2026.
The exercises also built on anti-submarine warfare activities conducted during previous engagements, allowing participating forces to refine shared procedures and maritime practices.
Notably, Australia and the US reaffirmed their support for freedom of navigation and overflight and the lawful use of the maritime domain in accordance with international law. Australia also reiterated that the 2016 South China Sea Arbitral Tribunal Award is final and legally binding on the parties.
The trilateral activity strengthens the Philippines’ network of defence partnerships amid continued tensions in the South China Sea. These recurring exercises with Australia and the US can improve maritime domain awareness, interoperability and readiness within its EEZ, while reinforcing its capacity to respond to potential maritime incidents.
The activity also supports the three countries’ stated commitment to freedom of navigation and international law, contributing to a broader regional security framework as ASEAN member states seek to manage competing maritime claims without escalating tensions.
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