India–Singapore defence cooperation has moved from symbolic engagement to operational interoperability. Examine with reference to SIMBEX.

SIMBEX began in 1994 as "Exercise Lion King". Its 33rd edition opened at Visakhapatnam in October 2026 [1], and it is the Indian Navy's longest continuous naval exercise with any country [2]. The exercise has largely moved from a goodwill drill to working interoperability, but it has not become an alliance.

From symbolism to an institutional base

• Continuity: Three unbroken decades mean each new generation of officers learns the other navy's procedures [1].
• Political backing: Ties became a Strategic Partnership in 2015 and a Comprehensive Strategic Partnership in 2024 [3]. The 2025 CSP Roadmap lists defence and security among its eight priority areas [4].

Markers of operational interoperability

• Combat in three dimensions: The SIMBEX-2026 Sea Phase in the Bay of Bengal covers anti-submarine, anti-surface and anti-air warfare [1].
• High-end platforms: SIMBEX-23 involved Indian ships, a submarine and LRMP aircraft [5], and SIMBEX-24 fielded a P-8I [6].
• Trust underwater: A Joint SOP on submarine rescue was signed in 2023 [7]. Navies share such details only with trusted partners.
• Logistics beyond the drill: Under the 2018 Implementation Agreement on mutual logistics and services support, each navy has deployed ships from the other's bases [8].
• Information sharing all year: Singapore has posted a liaison officer at India's IFC-IOR [9].
• Shared chokepoint: More than 40% of India's seaborne trade passes through the Malacca Strait [10]. Practising anti-submarine warfare in the Bay of Bengal prepares both navies for the waters where a threat to shipping would matter most.

Limits: interoperability without obligation

• Modest scale: The RSN sent only one ship in 2024 (RSS Tenacious) [6] and one in 2026 (RSS Supreme) [1].
• No commitment: The drills are scripted, and neither country promises to help the other in a crisis.
• Asymmetry: Indian cargo still transships via Singapore because Indian ports lack deep-water berths [11].

SIMBEX has therefore grown from symbolism into a lasting system of logistics, rescue and information-sharing, though it stops short of an alliance. India should make use of the logistics pact routine, feed SIMBEX lessons into IFC-IOR, and build the Great Nicobar transhipment port [11]. These steps would make the partnership more equal and support the shared goal of a peaceful, stable Indo-Pacific [1].