Since the establishment of relations in 1972, India-Vietnam relations are generally considered one of the most stable in the Asian geopolitical landscape. The two countries have maintained a traditional basis of friendship, moderate economic cooperation, and gradually expanded their defense commitments without creating major strategic problems for other major powers. Compared to hot topics such as the Sino-US rivalry, the Taiwan issue or the South China Sea conflict, India-Vietnam relations have rarely been the focus of international policymakers’ attention.
However, this is changing rapidly.
China appears to be closely following the development of India-Vietnam relations, particularly in the areas of defence, maritime affairs and strategic technology. Although China probably does not view this development as a direct threat to its national security, its real concern lies in the increasingly evident convergence of strategic interests between the two countries in areas where China holds significant interests, such as the South China Sea, the Indian Ocean, and a post-US security architecture in Asia.
For a long time, China was relatively comfortable in India-Vietnam relations because cooperation between the two countries was largely symbolic. In fact, since the two countries established a Comprehensive Strategic Partnership (CSP) in 2016defense activities were mainly limited to exchanges of delegations, small-scale exercises and political dialogue. But in recent years, China has seen this relationship become more substantial at a much faster pace.
Currently, India-Vietnam defense relations are no longer focused solely on friendly diplomatic statements. Both sides expand cooperation in areas of deeper strategic importance, such as underwater training, fighter pilot training, defense industry cooperation, maritime situational awareness sharing, and defense appropriations support. In particular, Vietnam’s access to the BrahMos supersonic cruise missile is becoming a symbol of growing strategic trust between Hanoi and New Delhi.
During Lam’s general secretary visit to India From May 5 to 7, the two countries took their relations to a new level – “Enhanced Comprehensive Strategic Partnership” – and signed a joint declaration focused on mutual assistance in defense industry development and maritime support.
From China’s perspective, these individual factors may not be enough to shift the regional military balance. But viewed holistically, they reflect a much broader trend: India is gradually moving from its position as the center of power in South Asia to that of an increasingly important security actor in Southeast Asia and the South China Sea.
China’s geostrategic concerns
From ancient times to the present, China has regarded Southeast Asia as a space where he has an exclusive influence due to its geographic location, economic size and commercial dependence on the Chinese market. However, with the growing presence of the United States, Japan and Australia, and now India’s growing involvement in security matters in Southeast Asia, China’s strategic environment is becoming much more complex.
In this context, Vietnam has become India’s most important partner in mainland Southeast Asia. Vietnam has an advantageous strategic position on the western coast of the South China Sea, has relatively strong military capabilities within ASEAN, and pursues a foreign policy flexible enough to cooperate with several major powers simultaneously.
The South China Sea is at the heart of this concern. For China, the South China Sea is not just the site of overlapping territorial disputes but a space linked to its “fundamental interests“, a question of survival. It is a crucial strategic shipping lane for China’s trade and energy, and a key area for China’s ambition to become a global maritime power. China’s ability to project naval power in the Western Pacific and maintain its nuclear deterrent capabilities at sea is closely linked to its control and influence in the South China Sea.
China is therefore particularly sensitive to the strategic presence of external powers in the region where it considers itself the center of order. From China’s perspective, India’s growing role in the South China Sea through cooperation with Vietnam has implications that extend beyond bilateral relations.
The oil and gas activities of ONGC Videsh in Vietnamese waters have repeatedly drawn objections from China, which claims these projects are located in a “disputed” area. However, India maintained its presence despite diplomatic pressure from China. This sends an important signal that India no longer sees itself simply as a South Asian or Indian Ocean power, but views the South China Sea as part of its growing strategic interests. This is increasingly taking shape through India’s “Act East” strategy, which New Delhi has been striving to strengthen since 2014. And Vietnam is the most important gateway for this expansion.
No issue better reflects the evolving relationship between India and Vietnam than the potential sale of the BrahMos missiles. Reports of Vietnam’s interest in the BrahMos have been persistent, although the Vietnamese Ministry of Defense has never publicly confirmed it. Militarily, the BrahMos could significantly enhance Vietnam’s anti-access/area denial (A2/AD) capabilities in the South China Sea. But what worries China most is the deeper meaning of this agreement. If India transfers the BrahMos to Vietnam, it would reflect India’s desire to play a more active security role in Southeast Asia, a significant increase in strategic trust between the two countries, and the gradual development of flexible defense cooperation networks outside the traditional multilateral framework by mid-sized Asian nations.
China may be accustomed to direct competition from the United States – a rival with a clear alliance structure and easily identifiable strategic logic. But “soft balancing” networks are much more difficult to counter. In this model, countries do not openly oppose China, but coordinate step by step to limit Beijing’s ability to completely dominate the regional order.
Relations between India and Vietnam were most likely perceived by China according to this model. Here, Vietnam’s policy towards China is also a key factor. Vietnam’s multilateralism and strategic autonomy make its partnerships – including with India – more unpredictable for China. In other words, China’s concern is not that Vietnam is “picking sides,” but rather that Vietnam’s flexible foreign policy contributes to a strategic environment that is increasingly unfavorable to China’s regional ambitions.
Lingering Limitations and Concerns
China also understands the limitations of Indo-Vietnamese relations. Vietnam maintains itspolicy of four no’s and avoids joining military alliances against China. India itself has a strong tradition of strategic autonomy and does not want to be seen as a tool in the US strategy to contain China. This makes it difficult for Indo-Vietnamese cooperation to transform into a military alliance in Asia.
Furthermore, relations between the two countries still face practical limits in terms of India’s economic scale, technological integration and defense industrial capabilities. China understands that current relations between India and Vietnam are not enough to fundamentally alter the regional balance of power.
But what catches China’s attention is not the current trend but the long-term trend. Relations between India and Vietnam reflect the reality that middle powers are increasingly seeking to build, strengthen and expand cooperative networks to protect their strategic space in the context of great power competition. And this is perhaps the most profound reason why China is monitoring India-Vietnam relations more closely. This is not because Vietnam and India are on the verge of forming a formal military alliance, but because the two countries are gradually creating a form of strategic convergence sufficient to make the security environment in the Indo-Pacific much more complex and difficult to control than before.