Beneath the waves, above the seas: Is India’s Kalvari-Vikrant duo Pakistan’s worst nightmare?

The Indian Navy’s deployment of INS Vikrant, its indigenous aircraft carrier, alongside the stealthy Kalvari-class submarines following the Pahalgam terror attack on April 22, 2025, has reshaped the strategic landscape in the Arabian Sea. With tensions escalating between India and Pakistan, this formidable combination signals India’s naval dominance and its intent to deter its western neighbour. A key question arises: can the Kalvari-class submarines carry nuclear warheads, and how does this capability—or lack thereof—strengthen India’s deterrence against Pakistan? This article explores the Kalvari submarines’ armament, their role in India’s naval strategy, and how they, alongside INS Vikrant, create a powerful deterrent, all while clarifying the nuclear question.

The Kalvari-class submarines, built under Project 75 with French collaboration, are diesel-electric stealth platforms designed for silent, undetectable operations. These submarines, including INS Kalvari, INS Vagir, and the recently commissioned INS Vagsheer, are equipped with Exocet SM-39 anti-ship missiles, which have a 70 km range and carry a 165 kg conventional warhead. A single missile can sink a 3,000-tonne ship or destroy critical infrastructure like Pakistan’s Karachi or Gwadar ports. Additionally, they can deploy up to 30 naval mines to disrupt maritime routes and carry SUT torpedoes for anti-submarine and anti-surface warfare. However, there is no official confirmation or credible evidence that Kalvari-class submarines are designed to carry nuclear warheads. These submarines are primarily conventional platforms optimised for anti-ship, anti-submarine, and mine-laying roles. India’s nuclear-capable submarine assets are limited to its Arihant-class ballistic missile submarines (SSBNs), like INS Arihant and INS Arighat, which carry K-15 Sagarika or K-4 missiles with nuclear warheads. The Kalvari-class, being smaller diesel-electric attack submarines (SSKs), lack the infrastructure, such as vertical launch systems or missile tubes, needed for nuclear ballistic or cruise missiles.

This distinction is critical. While the Kalvari submarines do not contribute to India’s nuclear triad, their conventional firepower is a significant deterrent. Their ability to stealthily approach Pakistan’s coastline, strike naval assets, or blockade ports like Karachi, which handles over 60% of Pakistan’s trade, poses a severe economic and military threat. By deploying mines or sinking ships, these submarines can choke Pakistan’s supply lines, disrupting oil imports and exports. This capability, combined with their near-undetectable nature, creates a psychological and strategic advantage, forcing Pakistan’s navy to rethink its maritime strategy.

INS Vikrant amplifies this deterrence. Operating 600–700 km from Pakistan’s coast, Vikrant is a floating airbase with MiG-29K jets capable of striking targets 800 km away, Kamov-31 helicopters for early warning, and HAL Dhruv for anti-submarine roles. Protected by Barak-8 missiles and advanced EL/M-2248 MF-STAR radars, Vikrant is a tough target. Its Carrier Battle Group, including Kolkata-class destroyers, Talwar-class frigates, and Kalvari submarines, forms a multi-layered shield and sword. While Vikrant’s aircraft are not nuclear-capable, their precision strikes can target Pakistan’s coastal infrastructure or naval bases, complementing the submarines’ covert operations. Together, they dominate the Arabian Sea, projecting power without needing nuclear escalation.

Pakistan’s navy pales in comparison. Its ageing Agosta 90B submarines and limited frigates struggle against India’s modern fleet. The upcoming Chinese-built Hangor-class submarines, meant to rival the Kalvari-class, are not yet fully operational. Satellite imagery from April 2025 showed most Pakistani submarines docked, highlighting their vulnerability. Pakistan’s reliance on Chinese and Turkish upgrades also risks supply chain issues, unlike India’s growing indigenous capabilities. A naval blockade by India could cripple Pakistan’s economy, as Karachi’s disruption would halt trade, creating domestic pressure on Islamabad.

The deterrence lies in India’s ability to dominate without nuclear weapons. The Kalvari submarines’ conventional strikes and Vikrant’s air superiority create a credible threat of overwhelming retaliation if Pakistan escalates tensions. Posts on X after Vikrant’s deployment noted Pakistan’s unease, with Islamabad conducting missile tests in the Arabian Sea as a show of defiance. Yet, these tests underscore Pakistan’s limited ability to counter India’s naval edge. Economically, a blockade could devastate Pakistan, while diplomatically, India’s naval presence signals to China, Pakistan’s ally, that New Delhi controls the Indian Ocean Region.

Risks remain. Pakistan’s C-802A and SMASH missiles could threaten Vikrant, though its defences mitigate this. Pakistan’s future submarine upgrades with Air Independent Propulsion (AIP) may narrow the gap, but India’s plan to retrofit Kalvari submarines with indigenous AIP by late 2025 will maintain its lead. X users have raised concerns about Vikrant’s vulnerability, but its escorts and mobility reduce risks.

In conclusion, while Kalvari-class submarines do not carry nuclear warheads, their conventional capabilities, paired with INS Vikrant’s dominance, create a robust deterrent against Pakistan. By threatening economic lifelines, controlling the seas, and projecting power, India ensures Pakistan hesitates to provoke further. This naval strategy, rooted in stealth, precision, and overwhelming force, proves that deterrence need not rely on nuclear might—it thrives on strategic dominance.