Exercise Cope Thunder 2025: Boosting Philippines-US Defense Cooperation

The Diplomat

18-07-2025

The Philippine Air Force (PAF) and the United States Pacific Air Force (PACAF) held the second part of this year's Cope Thunder exercise from July 7 to July 18 at Clark Air Base in Pampanga. Lt. Gen. Arthur Cordura, the PAF commanding general, and Lt. Col. Bryan Mussler, the commander of the 421st Fighter Squadron, PACAF, led the opening ceremony.
Cope Thunder, which was founded in the Philippines in 1976, moved to Eielson Air Force Base in the U.S. state of Alaska in 1992 and changed its name to Red Flag Alaska. It then moved back to the Philippines, taking the Cope Thunder name, in 2023. From its inception, the exercise was created to provide aircrews experience with combat in a realistic training setting. The drill swiftly developed into the 'premier simulated combat airpower employment exercise' for the PACAF. Cope Thunder's objective was to improve the aircrews' chances of surviving in war situations.
Cope Thunder provides a unique opportunity to strengthen interoperability and integrate troops between the U.S. and Philippine air forces. The goal of the contemporary Cope Thunder exercises is to improve alliance preparedness and joint interoperability among participating units by facilitating bilateral fighter training with the Philippine Air Force.
The July exercises expanded on the first portion of Cope Thunder held held from April 7-April 18, 2025. The latest iteration involved a greater number of PAF personnel and more realistic drills to prepare the allied partners for greater security challenges. With a focus on improving alliance interoperability and bilateral fighter integration, the exercise involved over 2,500 people, including 2,300 from the PAF and 225 from the PACAF.
As part of the aerial combat exercises between Washington and Manila, U.S. Air Force F-35s conducted their first flight over Philippine land. The F-35 is capable of gathering and sharing real-time battlefield intelligence through advanced sensors and data links, further allowing it to coordinate with other forces and direct operations across land, air, and sea. Two years ago, the Air Force sent its other fifth-generation fighter, the F-22 Raptor, to the Philippines for the initial Cope Thunder exercises. Embedding fifth‑gen U.S. aircraft within Philippine drills advances a forward‑deployed deterrence posture, reinforcing Philippine-U.S. alliance commitments in the face of regional security pressures.
Furthermore, particularly under the Enhanced Defense Cooperation Agreement (EDCA), which permits the U.S. military to access and use designated Philippine military bases for joint training, exercises, and humanitarian assistance, the F-35 deployment seems to validate the Philippines' growing role as a crucial frontline state in containing China. Notably, in spite of Beijing's opposition, Manila allowed the U.S. access to four more EDCA sites in 2023, increasing the total to nine.
The Philippines and the United States signed a treaty on mutual defense in 1951. An attack on either side would force the Philippines-U.S. alliance to respond and 'meet the common dangers' – a provision that may come into play in the South China Sea, where Beijing and Manila have conflicting claims to islands and reefs. The 1951 U.S.-Philippines Mutual Defense Treaty commitments are reflected in their joint exercises and military training, highlighting common objectives of increasing preparedness, bolstering deterrence, and promoting peace and stability throughout the Indo-Pacific region.
The deployment of F-35s to the Philippines is a significant development in U.S. strategy in Southeast Asia. The Philippines and other U.S. allies are being actively integrated into a larger nodal defense network. In addition to enhancing Manila's defense capabilities to support the U.S. in a potential conflict in the South China Sea or Taiwan, the Cope Thunder exercise provided an opportunity to test the cooperation between U.S. F-35s and Philippine FA-50s. The exercise involved comprehensive training across air and ground domains, which further reinforces the Philippine-U.S. defense bond and signals forward regional deterrence. The exercise would perhaps enhance the PAF's tactical evolution and readiness benchmarks, paving the way for future aircraft acquisitions and deeper strategic operations.
Given its geographic location, the Philippines is an essential ally for the U.S. defense of Taiwan. General Romeo Brawner, chief of staff of the Armed Forces of the Philippines, issued a warning in April that China was attempting to infiltrate the Philippine military and other institutions and that, in the event that Taiwan was invaded, the Philippines would 'inevitably' be engaged.
China is the biggest threat to U.S. security, according to the Trump administration. Furthermore, more than any other region, Washington's long-term objectives are rooted in the United States' relative position in the Indo-Pacific. Therefore, to counter China's aggression, the United States has been investing in its security alliances with allies who have the political will to go above and beyond.
Amid the Trump administration's halt on foreign aid, the United States exempted $336 million on February 21 for the modernization of the Philippine security forces. Cope Thunder 2025 also contributes to the Philippine military's modernization and capability development efforts to maintain regional security and stability in the Indo-Pacific region.
The exercise also marks another important milestone in the advancement of joint interoperability and mutual defense readiness between the PAF and PACAF. Given the Philippines' ongoing strategic significance, the Philippines-U.S. alliance is expected to continue to play a significant role in the Indo-Pacific region. Both the Philippines and the United States are hopeful that their partnership will continue to grow and that security cooperation will continue in the years to come.