The Nilgiri-class, designated Project 17A (P-17A), is a class of seven multi-mission stealth guided-missile frigates being built for the Indian Navy as a follow-on to the Shivalik-class (Project 17). The class incorporates a further-reduced radar cross-section, lower infrared signature, and improved combat systems, representing the current benchmark for Indian frigate design.[1]
Designed by the Indian Navy’s Warship Design Bureau, the seven-ship Project 17A programme is split between two shipyards: four ships built by Mazagon Dock Shipbuilders Limited (MDL) in Mumbai and three by Garden Reach Shipbuilders & Engineers (GRSE) in Kolkata, a dual-yard construction model intended to compress the overall delivery timeline compared to single-yard production.
The lead ship, INS Nilgiri, was commissioned on 15 January 2025. The second ship, INS Udaygiri, was delivered on 1 July 2025 and commissioned simultaneously with GRSE-built INS Himgiri on 26 August 2025, marking the induction of two Nilgiri-class frigates to the Eastern Fleet in a single ceremony. The third ship, INS Taragiri, was delivered on 28 November 2025 and commissioned on 3 April 2026. INS Mahendragiri, the fourth and final MDL-built ship, was delivered on 30 April 2026 and commissioned on 11 July 2026. On the GRSE side, INS Dunagiri was delivered on 30 March 2026 and commissioned alongside INS Agray and INS Sanshodhak in a tri-commissioning ceremony held in Kolkata on 21 June 2026, completing the bulk of the class’s induction within an unusually compressed timeframe.[2]
Each Nilgiri-class frigate displaces approximately 6,670 tonnes fully loaded and measures around 149 metres (489 feet) in length, with a beam of about 17.7 metres (58 feet) and a draught of roughly 5.2 metres (17 feet). The design places heavy emphasis on stealth shaping, integrating enclosed mast structures, angled hull surfaces, and reduced acoustic and infrared signatures to lower detectability compared to the preceding Shivalik-class.[3]
For anti-surface warfare, the class carries eight vertically launched BrahMos supersonic anti-ship cruise missiles, capable of speeds up to Mach 3. Air defence is provided by 32 Barak-8 (MRSAM/LR-SAM) surface-to-air missiles housed in four eight-cell vertical launch systems, giving medium-to-long-range protection against aircraft and missiles out to roughly 100 km. An upgraded OTO Melara 76mm naval gun provides close-range anti-surface, naval gunfire support, and anti-air capability, complemented by close-in weapon systems and torpedo tubes for anti-submarine warfare.
The class integrates a modern multi-function radar and sonar suite feeding an advanced combat management system, with hangar and flight deck facilities to embark two multi-role helicopters for extended anti-submarine warfare and surveillance reach, consistent with the multi-mission role envisioned for the class.
The compressed 2025-2026 induction cadence, with multiple Nilgiri-class ships commissioned within months of each other from two separate shipyards, represents a significant acceleration in Indian frigate delivery compared to earlier classes. Once fully inducted, the seven-ship class will substantially expand the Indian Navy’s stealth frigate fleet, providing the numbers needed to escort carrier battle groups, patrol contested waters, and sustain forward naval presence across both the western and eastern seaboards.[4]
| Type | Multi-Mission Stealth Guided-Missile Frigate |
| Builders | Mazagon Dock Shipbuilders Limited (4 ships); Garden Reach Shipbuilders & Engineers (3 ships) |
| Displacement | ~6,670 tonnes (full load) |
| Length | ~149 metres |
| Key Weapons | 8 x BrahMos (VLS); 32 x Barak-8/MRSAM; 76mm OTO Melara gun; CIWS; torpedoes |
| Ships in Class | INS Nilgiri (2025), INS Udaygiri (2025), INS Himgiri (2025), INS Taragiri (2026), INS Mahendragiri (2026), INS Dunagiri (2026), plus one further hull |
| Aviation | 2 x multi-role helicopters |