United States – China

Understand

This theatre has no front line. The United States and China are not at war, and there is no open fighting between them or between China and Taiwan. What it tracks is military posture across the Western Pacific: the daily air and naval activity of the People's Liberation Army (PLA) and the China Coast Guard, US and allied deployments, exercises on both sides, and incidents at sea and in the air. The centre of gravity is Taiwan, which has been governed separately from the mainland since the Chinese civil war ended in 1949. Beijing claims Taiwan as part of its territory and has not ruled out the use of force to take it. Taiwan's government, formally the Republic of China, rejects that claim. The United States does not formally recognise Taiwan, but US law commits Washington to make defensive arms available to it, and the US is its main arms supplier.

The Taiwan Strait is about 180 km (110 miles) wide and about 126 km at its narrowest. Taiwan's outlying islands of Kinmen and Matsu sit just off the mainland coast, and the Penghu islands lie in the strait itself. A median line down the strait, drawn by a US Air Force general in 1955, never had legal status; Beijing says it does not exist, and PLA aircraft have crossed it routinely since 2022. Taiwan's air defence identification zone (ADIZ) covers most of the strait and part of the mainland coast. An ADIZ is not sovereign airspace: it is a zone a government declares in order to identify approaching aircraft early, so an ADIZ entry is a signal of pressure rather than a violation of territory. Taiwan's defence ministry publishes a daily count of the PLA aircraft and ships it detects around the island.

Taiwan sits in the middle of the first island chain, the string of archipelagos off the Asian mainland that runs from Japan and the Ryukyu Islands through Taiwan to the northern Philippines and Borneo. Japan's westernmost island, Yonaguni, lies about 107 km from Taiwan and has hosted a Japanese radar station since 2016. About 55,000 US active-duty personnel are based in Japan, most of the bases on Okinawa, and US Forces Japan is being upgraded to a joint operational headquarters. Farther east, Guam's Andersen Air Force Base is the only base in the Western Pacific that can permanently support US heavy bombers. In the East China Sea, China's 2013 ADIZ covers the Japanese-administered Senkaku Islands, which China also claims.

In the South China Sea the friction is mostly between China and the Philippines, a US treaty ally. At Second Thomas Shoal in the Spratly Islands, the Philippines keeps a small garrison on the BRP Sierra Madre, a navy ship it deliberately grounded in 1999, and China Coast Guard vessels have repeatedly blocked or harassed its resupply missions. At Scarborough Shoal, west of Luzon, Chinese coast guard and navy ships patrol a feature both countries claim. The annual US-Philippine Balikatan exercise has grown to include Japan, Australia, Canada, France and New Zealand as full participants.

The current phase of pressure began on August 4, 2022, when China launched large-scale exercises around Taiwan after a visit by US House Speaker Nancy Pelosi. Since then the PLA has kept up near-daily air and naval activity around the island and staged a series of named drills: Joint Sword in April 2023, Joint Sword-2024A and 2024B after President Lai Ching-te took office on May 20, 2024, Strait Thunder-2025A in April 2025 and Justice Mission-2025 in December 2025. The China Coast Guard has taken a growing role in these operations.

Parties

• China Claims Taiwan and conducts regular military and coast guard operations around it and in the South and East China Seas; map colours are not a judgment.
• United States Taiwan's main arms supplier without formal diplomatic ties; treaty ally of Japan and the Philippines with forces across the region.
• Taiwan Self-governed democracy led by President Lai Ching-te that rejects Beijing's sovereignty claim.
• Japan Hosts about 55,000 US troops and is arming its southwest islands near Taiwan.
• Philippines US treaty ally in disputes with China at Second Thomas Shoal and Scarborough Shoal.

Analysis

The named drills have become steadily more like rehearsals for a blockade. Strait Thunder-2025A on April 1-2, 2025 followed a March 13 speech in which Lai called the People's Republic a foreign hostile force; Taiwan counted at least 76 PLA aircraft and 15 warships on the first day. Justice Mission-2025, held on December 29-30, 2025, followed a US arms package for Taiwan worth more than $11 billion. It practised blockading the ports of Keelung and Kaohsiung, drew about 130 aircraft and drones over its first 24 hours, along with 14 navy and 14 coast guard vessels, and included 27 rockets fired into waters north and southwest of Taiwan, the first such fire since 2022. Some of its declared zones reached into Taiwan's territorial waters. As of early October 2026 it remains the most recent named exercise around Taiwan. Day-to-day pressure continues at a lower pitch: Taiwan reported 181 PLA aircraft incursions into its ADIZ in September 2026, fewer than in September 2024 or 2025, and the China Coast Guard made four incursions into the waters around Kinmen that month and circled Pratas Island on September 7-8.

In 2026 the contest has shifted toward diplomacy between the major powers. President Donald Trump made a state visit to Beijing on May 13-15, 2026, and Xi Jinping made a state visit to Washington on September 23-25. Beijing said Xi urged the United States to oppose Taiwan independence; Trump did not publicly address Taiwan during the visit, and the two sides extended their trade truce to January 10, 2027. A US arms package for Taiwan worth about $14 billion has been delayed; Secretary of State Marco Rubio cited supply-chain constraints, and Republican senators have pressed the administration to release Taiwan security funding. In Taipei, Lai's government has proposed a special defence budget of about T$1.25 trillion spread over several years, and local elections are due on November 28, 2026.

Around Japan and the Philippines, tensions have risen. On November 7, 2025, Japanese Prime Minister Sanae Takaichi told parliament that a Chinese attack on Taiwan could threaten Japan's survival, the legal condition for Japan to use force in collective self-defence. China responded with a travel advisory against Japan, and on December 6-7, 2025 Japan said Chinese J-15 fighters had locked fire-control radar on Japanese F-15s near the Miyako Strait while the carrier Liaoning was operating in the area. Chinese carriers have operated near Japan again in 2026, and Japan announced in February 2026 that it plans to place surface-to-air missiles on Yonaguni by 2031. In the South China Sea, the Philippines said China Coast Guard personnel boarded its boats on a Second Thomas Shoal resupply run on June 17, 2024, injuring eight sailors; a provisional arrangement on resupply followed in July 2024. On August 11, 2025, a China Coast Guard cutter chasing a Philippine vessel near Scarborough Shoal collided with a Chinese navy destroyer, and China declared a nature reserve at the shoal on September 10, 2025. Balikatan 2026 began on April 20 with Japan and Canada joining as full participants.

An escalation would most likely show first in posture. The indicators we watch are the announcement of a new named exercise by the PLA's Eastern Theater Command; declared live-fire, no-fly or maritime closure zones; coast guard boardings or inspections of shipping bound for Taiwan; sharp jumps in Taiwan's daily counts of aircraft, warships and official ships; carrier groups operating east of Taiwan or beyond the first island chain; the massing of amphibious and civilian roll-on ships; and mobilisation steps on the mainland, where a revised National Defense Mobilization Law took effect on October 1, 2026. On the allied side, the signals are US carrier and bomber movements, missile deployments in Japan's southwest islands and the northern Philippines, and spikes in Japanese fighter scrambles.

What to watch

• Whether the PLA stages a new named exercise around Taiwan after the 2026 Trump-Xi summits.
• Taiwan's daily counts of PLA aircraft, warships and coast guard ships, and any sustained surge.
• China Coast Guard patrols around Kinmen, Pratas and other outlying islands.
• Whether the delayed US arms package for Taiwan is released, and the fate of Taiwan's special defence budget.
• Chinese carrier operations near Japan and Japan's missile deployments in its southwest islands.
• Resupply missions to Second Thomas Shoal and Chinese barriers or patrols at Scarborough Shoal.

Data

Parties

China; United States; Taiwan; Japan; Philippines

Current phase began

August 4, 2022 (PLA exercises after the Pelosi visit)

Taiwan Strait

About 180 km (110 miles) wide; about 126 km at its narrowest

Latest named PLA drill

Justice Mission-2025, December 29-30, 2025

ADIZ activity

Taiwan reported 181 PLA aircraft incursions in September 2026; it publishes counts daily

US forces in Japan

About 55,000 active-duty personnel

Japanese scrambles

Record of 1,168 in fiscal 2016; Chinese aircraft the main target in recent years

Open fighting

None

Timeline

1. 2022-08-04China begins large-scale military exercises around Taiwan after a visit by US House Speaker Nancy Pelosi.
2. 2023-04-08The PLA begins the three-day Joint Sword exercise around Taiwan.
3. 2024-05-23The PLA begins Joint Sword-2024A, three days after Lai Ching-te's inauguration.
4. 2024-06-17The Philippines says China Coast Guard personnel boarded its boats on a Second Thomas Shoal resupply run, injuring eight sailors.
5. 2024-10-14The PLA stages Joint Sword-2024B around Taiwan.
6. 2025-04-01The PLA begins the two-day Strait Thunder-2025A exercise.
7. 2025-08-11A China Coast Guard cutter collides with a Chinese destroyer while chasing a Philippine vessel near Scarborough Shoal.
8. 2025-11-07Japanese Prime Minister Sanae Takaichi links a Taiwan contingency to Japan's survival, setting off a dispute with Beijing.
9. 2025-12-06Japan says Chinese J-15 fighters locked fire-control radar on Japanese F-15s near Okinawa.
10. 2025-12-29The PLA begins Justice Mission-2025, a two-day blockade rehearsal with live rocket fire.
11. 2026-04-20Balikatan 2026 opens in the Philippines with Japan and Canada as full participants.
12. 2026-05-13Donald Trump begins a state visit to China.
13. 2026-09-23Xi Jinping begins a three-day state visit to the United States.
14. 2026-10-01China's revised National Defense Mobilization Law takes effect.

Live events, aircraft and thermal anomalies for every theatre are published as GeoJSON on the data endpoints page.