# Taiwan Strait
> The 180-kilometer channel separating Taiwan from China's Fujian Province, where People's Liberation Army exercises and US Navy transits define Asia's most consequential territorial dispute.

**Meta:** type: reference · date: 2026-07-03 · heads:  · 4 takes · 2 lenses · 1 regions

## What it is

The Taiwan Strait is a 180-kilometer-wide channel separating the island of Taiwan, governed by the Republic of China, from Fujian Province on the People's Republic of China's mainland. At its narrowest point the strait spans 126 kilometers. It connects the South China Sea to the south and the East China Sea to the north, running almost entirely over the Asian continental shelf at depths below 150 meters. For global shipping it is a secondary lane, but as the front line of the most consequential unresolved sovereignty dispute in Asia it is the most closely watched stretch of water on earth.

Four actors define the balance. The PLA Navy and Air Force treat the strait as sovereign Chinese waters and have sharply increased their operational presence since 2020. The Republic of China Armed Forces defend from the main island and the offshore islands of Kinmen and Matsu. The US Seventh Fleet conducts regular transits to assert freedom of navigation. Japan's Self-Defense Forces, operating from Yonaguni Island roughly 110 kilometers east of Taiwan, are drawn into any contingency by geography alone.

## History

Two Cold War crises established the strait's political geometry. From September 1954, PLA artillery bombarded the Kinmen, Matsu, and Dachen islands; the US Congress responded in January 1955 with the Formosa Resolution, authorizing President Eisenhower to defend Taiwan and its offshore islands. A second crisis in August 1958 resumed bombardment of Kinmen; Washington resupplied Republic of China garrisons and Beijing de-escalated. A third crisis in 1995-96, triggered by US President Bill Clinton's decision to grant Taiwan's President Lee Teng-hui a visa, saw Beijing fire ballistic missiles into sea zones near Taiwan; the United States dispatched two carrier strike groups.

The 1979 Taiwan Relations Act committed the United States to supplying Taiwan with defensive arms and maintaining the capacity to resist forcible change of Taiwan's status. An informal centerline, roughly the midpoint of the strait, held as a de-escalation norm for decades. The PLA began routine crossings of that line after 2020 and Beijing officially declared the centerline nonexistent in 2022, asserting the entire strait as internal Chinese waters.

## Current state

PLA activity reached record levels in 2025. CSIS ChinaPower tracked 3,764 PLA air incursions into Taiwan's air defense identification zone during the year, up 22.4 percent from 2024. Average monthly PLA naval deployments around Taiwan rose to 221 vessels, 42 percent above the pre-May 2024 baseline. Two named exercises bookended the year: Strait Thunder-2025A in April (135 sorties, 38 naval craft) and the [Justice Mission-2025](/ja/n/china-taiwan-blockade-rehearsal-jun25) blockade rehearsal in December (eight exercise zones, 27 rocket launches), the tightest simulated cordon on record. The [Taiwan defense budget](/ja/n/taiwan-strait-pla-pressure-defense-budget) has accelerated in response, reaching roughly 2.4 percent of GDP for 2025, though analysts broadly argue Taipei needs to go considerably further.

The PRC's claim that the strait is internal Chinese waters is rejected by the United States, European Union, Japan, and Australia. US-led coalition exercises, including [RIMPAC 2026](/ja/n/rimpac-2026-pacific-exercise), signal that Washington intends to sustain a multilateral posture in the Pacific.

## Relationships

Taiwan and its partners have thickened maritime cooperation around the strait. The [four-power coast guard initiative](/ja/n/taiwan-four-power-coast-guard-jun24) draws Taiwan, the United States, Japan, and the Philippines into joint surveillance operations. Japan's geographic proximity means any Taiwan contingency is also a Japanese security event, as demonstrated by [PLA incursions near Yonaguni Island](/ja/n/japan-china-yonaguni-protest-jun29). Security think tanks running [coercion tabletop exercises](/ja/n/taiwan-coercion-tabletop-jun26) consistently identify a sustained maritime blockade, rather than an amphibious assault, as Beijing's most plausible near-term instrument, making contested shipping lanes the central strategic variable.

## What to watch

The cadence and geographic scope of named PLA exercises are the leading indicator; each iteration since 2022 has extended the simulated blockade perimeter closer to Taiwan. Watch whether European navies sustain freedom of navigation transits, making the strait a genuinely multilateral issue rather than a US-China bilateral one. Taiwan's first domestically-built submarine is due for sea trials after years of delays, a milestone that would meaningfully shift undersea deterrence calculus. Beijing's formal legal claim to the strait as internal waters is the framing contest beneath all the tactical movements, and its resolution, or entrenchment, will shape the legal architecture of the wider Indo-Pacific.

## Regional takes (batched by bias / lens)

### analysis
- **CSIS ChinaPower Project** (United States, en) — Tracks PLA air and naval activity around Taiwan in 2025; documents 3,764 ADIZ incursions (up 22.4%), two named exercises, and the 42% rise in average monthly naval deployments.
  Source: https://chinapower.csis.org/china-increased-military-activities-indo-pacific-2025/
- **Global Taiwan Institute** (United States, en) — Detailed breakdown of Justice Mission-2025, the largest PLA exercise around Taiwan by geographic reach, with eight operation zones and a record 90 centerline crossings on the first day.
  Source: https://globaltaiwan.org/2026/01/pla-justice-mission-2025/

### official record
- **US Department of State, Office of the Historian** (United States, en) — Primary record of the 1954-55 and 1958 Taiwan Strait crises, the Formosa Resolution, and the origins of the US commitment to resist forcible change of Taiwan's status.
  Source: https://history.state.gov/milestones/1953-1960/taiwan-strait-crises
- **US Department of Defense** (United States, en) — 2025 China military power report to Congress; documents PLA order of battle, Taiwan Strait balance of forces, and Chinese nuclear expansion as of end-2025.
  Source: https://media.defense.gov/2025/Dec/23/2003849070/-1/-1/1/ANNUAL-REPORT-TO-CONGRESS-MILITARY-AND-SECURITY-DEVELOPMENTS-INVOLVING-THE-PEOPLES-REPUBLIC-OF-CHINA-2025.PDF

## Across the graph
- Related: [[china-taiwan-blockade-rehearsal-jun25]], [[taiwan-strait-pla-pressure-defense-budget]], [[taiwan-four-power-coast-guard-jun24]], [[taiwan-coercion-tabletop-jun26]], [[rimpac-2026-pacific-exercise]], [[japan-china-yonaguni-protest-jun29]]
- Entities: Place:taiwan Strait, Taiwan, China, Person:xi Jinping, United States

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Canonical: https://rbtfl.xyz/ja/n/taiwan-strait-dossier