US presence in South China Sea noted

The United States maintained a strong military presence in and around the South China Sea in 2025, with increased close-in reconnaissance, joint exercises and alliance-based operations, a report revealed on Friday.

The South China Sea Strategic Situation Probing Initiative, a Beijing-based think tank, issued its annual report on US military activities in the South China Sea based on open-source data. The initiative has published such reports since 2019 to promote transparency and provide third-party assessments.

The report said that US military activities targeting China in the South China Sea have risen sharply since 2009. In 2025, although the US Navy and US Air Force were constrained due to tensions in the Middle East and other regions, Washington maintained a strong military presence in and around the South China Sea.

The US operations revealed mixed trends. Activities by carrier strike groups, amphibious ready groups, ocean surveillance ships and bombers showed signs of fatigue, largely due to deployments to hot spots and constraints on US manufacturing. The frequency of so-called "freedom of navigation" operations also declined.

However, close-in reconnaissance, drills and training, and joint operations with allies and partners increased significantly. Unmanned platforms accounted for much of the increase, with large US unmanned reconnaissance aircraft making up about 30 percent of US close-in aerial reconnaissance sorties targeting China in the South China Sea.

MQ-4C Triton and MQ-9 Reaper drones deployed in Okinawa, Japan, and at the Clark Air Base in the Philippines were key contributors to increased reconnaissance due to their long range, endurance and lower operational risks.

In 2025, US reconnaissance aircraft conducted about 1,200 sorties in the South China Sea, while ocean surveillance and survey vessels operated for 197 ship-days.

The report said that reconnaissance flights were more frequent at the beginning and end of the year. Sorties typically increased when China conducted major military deployments or when large US formations operated in the South China Sea.

The report noted that traditionally, US aerial reconnaissance missions in the South China Sea have departed from Kadena Air Base in Okinawa. In recent years, as US intelligence, surveillance and reconnaissance assets shifted toward forward bases in the Philippines, flights from Philippine bases have become more frequent.

At least 11 US nuclear-powered submarines appeared in the South China Sea and surrounding waters in 2025, demonstrating a deterrent role, the report said. US bombers carried out seven deployments involving 13 B-52H and B-1B sorties, fewer than in previous years.

The US Navy sent four carrier strike groups to the South China Sea nine times in 2025. Three of the groups were later redeployed to the Middle East.

Military experts said the report shows that US operations in the South China Sea are aimed not only at maintaining presence, but also at deterrence, intelligence collection, alliance coordination and battlefield preparation.

Hu Bo, director of the South China Sea Strategic Situation Probing Initiative, said that while such exercises do not substantially change the regional military balance or pose a major military threat to China, they are politically and diplomatically negative.

He added that their main objective is to heighten tensions and encourage the Philippines to continue actions targeting China.

Hu said the overall US strategy in the South China Sea has not changed significantly since 2009, but many activities have reached a ceiling due to pressure from other theaters and shortages of US military platforms, particularly warships. This has led to overdeployment and fatigue within the US military.

Zhang Junshe, a military commentator, said that the high frequency of US air, surface and underwater activities reflects Washington's latest national security and defense priorities, with the Western Pacific and the Asia-Pacific remaining key strategic areas.

He said that the US is trying to strengthen deployments along the so-called first island chain, maintain pressure on China and rally allies such as Japan and the Philippines. Increased operations by reconnaissance aircraft, warships, submarines and carrier groups are intended to support allies, especially the Philippines, and collect information on China's military movements.