India and the Philippines are preparing to take their defence relationship further, building on a partnership that has quietly become one of India's most important security relationships in Southeast Asia.

Prime Minister Narendra Modi and Philippine President Ferdinand Marcos Jr met on the sidelines of the BRICS Summit in New Delhi on Sunday, where the two leaders agreed to deepen cooperation in defence and security, alongside trade, investment, space, technology and infrastructure. The meeting came just over a year after the two countries formally elevated their relationship to a Strategic Partnership.

Defence has become one of the fastest-growing parts of that relationship. India and the Philippines now hold regular talks between their armies, navies and air forces, while their 2025-29 roadmap calls for expanded military training, maritime security cooperation, defence technology collaboration and greater interaction between their armed forces.

At the centre of this transformation is the BrahMos supersonic cruise missile. In 2022, Philippines signed a $375 million deal to acquire the Indian-Russian developed missile system, becoming its first foreign customer. India completed delivery of the three BrahMos batteries in April this year. The weapons give Philippines a powerful land-based capability to strike hostile ships approaching its coastline.

For India, the deal was much more than a successful defence export. It demonstrated that New Delhi could become a serious supplier of advanced military equipment to Southeast Asian countries looking to modernise their armed forces. The two countries have since discussed broader defence-industrial cooperation, including the possibility of co-development, co-production, technology exchanges and collaboration between defence companies.

For the Philippines, that cooperation comes at an important moment. Manila is rapidly strengthening its military capabilities as its maritime disputes with China continue in the South China Sea. Philippine and Chinese vessels have repeatedly confronted each other around contested waters and reefs, particularly near Scarborough Shoal and the Spratly Islands.

India has avoided becoming a direct participant in those disputes, but its position has become increasingly clear. New Delhi has repeatedly backed freedom of navigation, international law and the 1982 United Nations Convention on the Law of the Sea. It has also supported the 2016 arbitral ruling that rejected the legal basis for much of China's expansive claims in the South China Sea.

Interestingly, the South China Sea was not explicitly mentioned in India's official readout of Sunday's Modi-Marcos meeting. But the strategic backdrop is difficult to separate from the rapidly expanding defence relationship.

The partnership now extends beyond weapons. India and the Philippines want more military training, service-to-service exchanges, information sharing, naval and coast guard cooperation, port visits and participation in maritime exercises. Their strategic partnership also provides for cooperation in defence research, supply chains and potentially the joint production of military equipment.

The relationship is expanding outside defence as well. Modi and Marcos agreed to strengthen cooperation in space, fintech, railway infrastructure, science and technology, education and investment. Bilateral trade has already crossed $3 billion, while the Philippines has now joined the India-led Coalition for Disaster Resilient Infrastructure.

For New Delhi, the Philippines is becoming an increasingly important part of its Act East policy and its wider Indo-Pacific strategy. For Manila, India offers something equally useful: another major Asian partner capable of providing weapons, technology and diplomatic support without requiring the Philippines to depend entirely on its traditional Western allies.