Moscow/ New Delhi: In a notable development for India’s underwater defense strategy, Russia has offered to transfer three fully upgraded Kilo-class diesel-electric submarines to the Indian Navy as an interim capability solution while India’s indigenous Project 75I (P-75I) conventional submarine program continues to face delays.
The offer, reportedly valued at under $1 billion, underscores deepening defence ties between New Delhi and Moscow and highlights the Indian Navy’s pressing need to sustain and modernize its submarine fleet as regional maritime competition intensifies.
Background of India Russia Kilo-Class Submarines Upgrade Deal
India’s submarine fleet has long been the backbone of its undersea deterrence and maritime security architecture in the Indian Ocean Region (IOR), where it faces growing challenges from China’s expanding naval presence and modernisation of regional navies.
However, ageing diesel-electric submarines, particularly the Sindhughosh-class (Russian Kilo variants) inducted between the mid-1980s and 2000, are approaching the limits of their operational life, even with prior refits and upgrades undertaken over the years.
The Indian Navy currently operates a mix of conventional submarines, including Russian-origin Kilo boats, German Shishumar-class boats, and Indian-built Scorpene-class submarines, but fleet strength and capability gaps are growing as old hulls retire faster than replacements are commissioned.
The Russian Proposal: A Stopgap with Enhanced Combat Potential
As part of the proposal presented by Moscow, three upgraded Kilo-class submarines drawn from Russian Navy surplus stocks would be modernised and refitted before transfer to India.
Each submarine’s upgrade package is said to include:
- Installation of Klub-S missile systems (export variant of Kalibr) capable of launching anti-ship and land-attack missiles with ranges between ~220 km and 300 km.
- Low-observable stealth enhancements to reduce detection signatures.
- Potential integration of modern lithium-ion battery systems to improve submerged endurance and performance.
- Automated periscopes and upgraded combat suites aligned with modern submarine combat requirements.
Defense analysts describe the package as a cost-effective “breathing apparatus” for the Indian Navy — a necessary bridge until the next generation of submarines enters service. The upgraded diesel-electric boats are expected to receive life extensions of up to 20 years.
Importance of India Russia Kilo-Class Submarines Upgrade Deal
The urgency of this proposal stems largely from delays in India’s indigenous Project 75I submarine program — a marquee initiative under which India planned to build six state-of-the-art conventional submarines under the Strategic Partnership Model (SPM).
Originally conceived as a cornerstone of India’s deep-sea underwater capability expansion, P-75I has faced repeated procedural delays in evaluation and contract finalization.
Technical issues and vendor negotiations have dragged the project timeline, and formal contract signing has been pushed well into 2025–2026, with the earliest new submarine inductions not expected until the early 2030s.
Without such interim acquisitions, projections suggest the Indian Navy’s conventional submarine fleet could fall to single digits by the end of this decade, potentially undermining India’s undersea deterrence and strategic reach.
India Russia Kilo-Class Submarines Upgrade Deal: Strategic and Logistical Fit for India
Given its history of operating the Sindhughosh/Kilo series for decades, the Indian Navy would likely find logistical and training synergies with the additional Russian boats.
Existing dockyard infrastructure and crew training pipelines could absorb the refurbished submarines with minimal disruption, ensuring readiness during the crucial transition period.
This proposal follows discussions between Indian and Russian leaders, including assurances on other undersea assets such as a nuclear-powered Akula-class attack submarine lease by 2028, revealed during President Vladimir Putin’s visit to New Delhi.
Read also: Project 75I: India to Boost Submarine Force with Advanced Indigenous AIP-Equipped Submarines
