An Incomplete Report on US Military Activities in the South China Sea in 2021

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2022-03-27 | SCSPI


In peacetime, the conduct of highly-intensified military activities in another coastal state’s surrounding waters, such as thousands of close-in reconnaissance operations and hundreds of military exercises, is a clear violation of the spirit “maintaining international peace and security” of the UN Charter and "the peaceful uses of the seas" of the United Nations Convention of the Law of the Sea.

Since 2009, US military activities against China have strengthened in terms of the frequency and intensity. In 2021, there was a sharp rise in the US armed forces’ operations in the South China Sea compared with that in 2020, which poses increasingly high risks of China-US friction and conflict in the air and at sea.

In 2021, the US military strategy and operation on the South China Sea is featured by deterrence----strengthening forward military presence and targeted activities, to deter the imaginary “China might overreach”. However, over-deterrence will stimulate China’s decisive countermeasure, thus inevitably be backfired. In the future, deterrence and counter-deterrence, provocation and counter-provocation will be most critical strategies and tactics of US-China maritime interaction.

US military’s presence and operations in the South China Sea are the major factor affecting South China Sea situations. Since 2019, South China Sea Strategic Situation Probing Initiative (SCSPI) has released a yearly report An Incomplete Report on US Military Activities in the South China Sea. The report is intended for promoting the transparency of South China Sea Situations and providing the perspective of a third-party think tank for reference to government departments, research institutions, media and the public of related parties.

                                                                                                                                                                                                                                                          Director of SCSPI   Hu Bo                                                            


Key Findings

In 2021, the US placed great emphasis on military deterrence against China, and maintained highly-intensified military activities in the South China Sea, such as close-in reconnaissance, forward presence, “freedom of navigation operations (FONOPs)”, military exercises and drills, and battlefield preparation.

  • The US military deployed four CSGs, two ARGs, 11 SSNs, and  22 bomber bomber sorties to the South China Sea with a high tempo.
  • Around 1,200 sorties of large reconnaissance aircraft conducted close-in reconnaissance over the South China Sea. The US ocean surveillance ships and oceanographic survey ships conducted frequent operations in the waters for a total of 419 ship-days at sea.
  • According to open source data, the US military carried out a total of 95 large-scale exercises and drills, including 14 unilateral exercises and 81 bilateral and multilateral ones.


In 2021, the US warships and aircraft’s frequent transits through the Taiwan Strait and US officials’ visits to Taiwan released dangerous signals to separatists in Taiwan and extremely threatened the peace and stability of the Taiwan Strait.

  • The US warships crossed the Taiwan Strait for 12 times, more specifically, 5 times north to south and 7 times south to north.
  • US reconnaissance aircraft joined Taiwan Strait transit operations for the first time.
  • The US military made first joint transit of the Taiwan Strait along with other countries’ warship (Canada).


In 2021, the U.S. strategic vision is shifting from strategic competition to integrated deterrence, with a combat concept focused on operational and actual combats with concepts of operations (CONOPS), and seeking to create a new generational gap with China in military equipment and technology.

  • The core of America’s defense strategy is integrated deterrence, a term that includes having the best weapons systems, the latest technologies, and new CONOPS that make adversaries think twice.
  • US military against China in the Indo-Pacific region, including: 1) denying China sustain air and sea dominance inside the first island chain in a conflict; 2) defending the first-island-chain nations, including Taiwan region of China; 3) maintaining all-domain advantage outside the first island chain.


In 2021, the US made greater efforts to pull extra-regional countries to involve militarily in the South China Sea, as China-US competition intensifies.

  • In terms of diplomatic instruments, the US directed agenda-setting under multilateral mechanisms as the Quadrilateral Security Dialogue (QUAD) and Group of Seven (G7) to continuously hyper the South China Sea issue and exert diplomatic pressure to China. In terms of military means, the US conducted joint military exercises to increase air and sea interoperability with its allies.
  • US enhanced the effect of its allies in new CONOPS. In addition to vigorously strengthening the U.S.-Japan alliance, the US has also focused on enhancing the role of other allies, such as deploying attack nuclear submarines and strategic bombers in Australia and reintroducing Subic Bay as a key forward base for power projection into the South China Sea.




I. Significantly Intensified Strategic Platforms’ Activities

II. Further Expanded Close-in Reconnaissance

III. Frequently Stirring up the Taiwan Strait Situation

IV. Military Exercises and Drills’ Recovery and Scale-up

V. Evolution of Maritime Strategies, CONOPS and Equipment

Ⅵ. Conclusion


Please download PDF for full report.


With a view to maintaining and promoting the peace, stability and prosperity of the South China Sea, we launched the South China Sea Strategic Situation Probing Initiative (SCSPI) in April of 2019. The Initiative aims to integrate intellectual resources and open source information worldwide and keep track of important actions and major policy changes of key stakeholders and other parties involved. It will provide professional data services and analysis reports to parties concerned, helping them keep competition under control, and with a view to seek partnerships.