The South China Sea is Facing ADIZ Threat from China

By John Hoang, Esq.

The South China Sea with ADIZ
The situation in the South China Sea area continues to be tense with “threats” because China would announce the establishment of an “air defense identification zone” (ADIZ) in the South China Sea.

On May 5, Taiwanese media quoted Taiwan’s Defense Minister Yen Te-fa as saying Beijing was preparing to establish an Air Defense Identification Zone (ADIZ) in the South China Sea.

Taiwan’s Ministry of Defense stated that although China had announced that it would establish an ADIZ in the South China Sea, Beijing had not officially announced it. The Philippines ADIZ is currently the only designated airspace in this disputed area.



Recently, the South China Morning Post on May 31, citing a military source of the People’s Liberation Army (PLA), revealed that Beijing was planning to establish an air defense identification zone (ADIZ) in the South China Sea since 2010. In the same year, China said it was considering announcing similar airspace control measures in the East China Sea, a move that has received widespread criticism.

Some officials in the Chinese military said that plans to control airspace over the South China Sea – one of the world’s most fierce disputed maritime routes, had been prepared for a decade.

The South China Morning Post reported that according to an unnamed source from the People’s Liberation Army (PLA), ADIZ was proposed in the South China Sea including the Pratas Islands, and Paracels, and Spratly Islands. Plans for the area have been around for a long time, such as the ADIZ plan for the East China Sea – which Beijing said it considered in 2010 and announced in 2013. The source said that more Chinese authorities are waiting for a suitable time to announce ADIZ in the South China Sea. Although Beijing may have been discreet about this issue, Taiwan’s Ministry of Defense on May 4 announced that it was aware of mainland China plans.

What is ADIZ?
The Air Defense Identification Zone (ADIZ) is simply understood as the range of airspace assigned by a country and requires all vehicles flying over this area to be identified, and be controlled by that country. ADIZ is not synonymous with national airspace, but due to national requirements, it is regarded as a coexistence zone with the national security and defense area.

ADIZ can be considered as a product of the Cold War era and is still maintained today. In addition to the US, India, Japan, Norway, Pakistan, Korea, the United Kingdom, China and Taiwan have established ADIZ.

Currently, there is no international agreement or institution governing this issue, which states are not explicitly prohibited or permitted by law to establish such an ADIZ. Therefore, the countries that set up ADIZ mainly rely on their own arguments to explain their establishment. It should also be added that ADIZs may include areas and ranges that lie outside the airspace of nations (which may cover the airspace above exclusive economic zones), and they cannot be used to justify the expansion of airspace.

Similar to the principle of “The land dominates the sea” in the law of the sea, the scope of the ADIZ must have a logical link to the territory of the claimant state. This means that a country cannot automatically claim that an international airspace is under its control if there is no basis to prove its sovereignty over the territories below it. For the same reason, such ADIZs cannot be established in disputed territories because they will create tensions and conflicts of territorial sovereignty between the countries concerned.

That means that although there is no clear regulation on the establishment of ADIZ, China cannot have a legal basis if it declares an ADIZ on the South China Sea area, which is a subject of many countries involved.

Purposes of declaring ADIZ of China
Initially, ADIZ under the Cold War only applied to military aircraft. In these cases, ADIZ is used as an early warning “mechanism”. This was the original purpose of ADIZ when the US first created it during the Cold War to reduce the risk of a sudden Soviet attack in the air.

But in the case of ADIZ in the East China Sea area in 2013, China was obliged to apply to civil aircraft. Thus, beyond the military field, China’s ADIZ can also be a means for Beijing to implement the following legal, strategic and political purposes:

  • In legal terms, ADIZ can be considered as a no-entry zone, meaning the establishment of ADIZ can provide a legal basis for foreign aircraft to fly into certain areas. In addition, ADIZ can be used with the function of expressing sovereignty. Although ADIZ is not a territorial claim, it can be used to exercise some form of sovereignty and manage airspace over a territory. The acceptance or submission of the foreign aircraft may then be interpreted as an acknowledgment that the country possessing ADIZ is exercising sovereignty over a territory.

  • Regarding strategy: ADIZ will be used by China as a “card” to bargain with other countries, especially ASEAN countries that have direct interests in the South China Sea. ADIZ will help China gain more position in the “chess board” with other countries.

  • Politically, ADIZ will be a means for Xi Jinping and the Chinese Communist Party to use to show determination, enforcement capacity, and ability to cope with reactions of countries in the region and around the world especially in the context of China’s internal political turmoil, when Beijing is under the impact of the US-China trade war and the COVID-19 pandemic. Chinese leaders want to use ADIZ as a means convenient to placate domestic discontent.

In addition, ADIZ is also a message that Beijing wants to express with the function of preventing other countries from doing things that Beijing does not want.

What does ASEAN need to do?
Declaring the establishment of ADIZ in the South China Sea will increase tensions with the United States and may damage relations between Beijing and neighboring Southeast Asian countries. China has sought to build closer ties with its Southeast Asian neighbors in recent years, but China risks jeopardizing those relationships if Beijing declares to establish ADIZ. in the South China Sea. Such a statement would seriously damage China’s relations with Southeast Asian nations, which, to date, have largely been implicitly accepting Chinese aggression and provocations, including land reclamation and militarization of maritime features. However, if China declares to establish the ADIZ, it will be forced to choose, not between the US and China but between its economic relationship with China and its own sovereignty.

Malaysia, Philippines, Vietnam, and Brunei are among the ASEAN countries directly involved in the South China Sea dispute. Countries like Indonesia and Singapore are also greatly affected by tensions in the East Sea. Therefore, if China declares an ADIZ, it will be extremely detrimental to most ASEAN countries. If in 2013, when China declared ADIZ in the East China Sea area, countries like Japan and the United States directly challenged this statement by flying aircraft into this area without Chinese permission. However, with its air potential, it is difficult for ASEAN countries to challenge China similarly if China declares ADIZ in the South China Sea.

Therefore, a common ASEAN stance (if it can be implemented rather than just on paper) along with the Code of Conduct will play an important role to prevent any escalation.

In the past, Vietnam has clearly expressed its attitude when it proposed a content in the Draft Code of Conduct in the South China Sea (COC) as “no country can unilaterally declare ADIZ in the South China Sea.” Perhaps, Vietnam, as the rotating Chair of ASEA, needs to persistently reiterate this view and persuade ASEAN countries to agree with this content.

However, the Code of Conduct may be a mere document, existing on paper and not implemented in practice, unless Southeast Asian countries can find alternatives to China is in the economic field and rebalancing its position to gain a stronger position in the negotiations.

It is also important that ASEAN uses the levers it holds, such as ASEAN’s relations with other powers, to counter China’s aggressive behavior in the South China Sea.


ATTY. JOHN HOANG is the National Youth Movement for West Philippine Sea (NYMWPS) Vietnam Country Chair and Consultant who is an expert in International law and Law of the Sea.


Any opinions, advice, or statements contained in this article are those of the writer and/or the organization represented, and do not necessarily reflect the opinions of the Hawaii Filipino Chronicle’s editorial board.


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