Undersea Deterrence Crisis: How Operation Sindoor Deepened Doubts About Pakistan’s Submarine Capabilities

Operation Sindoor has cast a harsh spotlight on what is now widely recognised as the Pakistan Navy’s most critical strategic weakness: its undersea warfare capabilities.

Far from being the silent backbone of deterrence, Pakistan’s submarine fleet was found wanting at a moment of acute regional tension, exposing both operational paralysis and deep-rooted structural vulnerabilities.

As revealed by the former in an interview with an Indian daily, Navy Chief Admiral Sunil Lanba, Pakistan’s navy was forced to halt all maritime activities along its coastline, keeping its fleet, including submarines, confined to coastal waters rather than risking deployment in contested zones. 

These operational gaps were highlighted by satellite imagery and open-source intelligence indicating that several of Pakistan’s Agosta-class submarines remained inactive, docked for prolonged maintenance cycles, with at least one observed stranded ashore.

The inability to mobilise these critical assets during a period of heightened conflict, coupled with delays in upgrades due to dependency on Chinese and Turkish support, exposed a glaring gap in Pakistan’s deterrence posture, especially when contrasted with India’s credible and operationally ready SSBN fleet.

Operational Paralysis and Satellite Revelations

Recent satellite imagery from March 2025 revealed a stark reality—only two of Pakistan’s five Agosta-class submarines were operational, while the remaining three were docked for extended maintenance at Karachi Shipyard. One Agosta-90B submarine was even observed stranded ashore, a vivid symbol of the fleet’s readiness crisis. These prolonged maintenance cycles, particularly involving critical overhauls of MESMA air-independent propulsion systems and structural upgrades, have been plagued by repeated delays, largely due to supply chain disruptions and dependence on Turkish and Chinese technical support.

Dependency and Delays: The Hangor-Class Challenge

Pakistan’s efforts to modernise its submarine fleet through the acquisition of eight Hangor-class submarines from China have also encountered significant delays. While the first two units—PNS Hangor and Shushuk—are still under construction in China, their delivery has slipped to late 2025 and 2026, with local assembly at Karachi Shipyard further hampered by budgetary and liquidity constraints. The slow pace of construction and fiscal challenges threaten to extend Pakistan’s capability gap well into the next decade.

The Global Firepower Index 2025 reported that Pakistan operates a fleet of eight submarines, primarily Agosta-class and Chinese Yuan-class, but its undersea capabilities are limited to coastal defence and regional operations, lacking the strategic depth of nuclear-powered platforms. 

Second-Strike Credibility in Question

The operational limitations of Pakistan’s submarine fleet have direct implications for its strategic deterrence posture. Although the Babur-3 submarine-launched cruise missile is touted as a cornerstone of Pakistan’s second-strike capability, independent analysts question its effective range and operational reliability, especially given the limited underwater endurance of diesel-electric Agosta-class submarines. Unlike nuclear-powered submarines, which can remain submerged for months, Pakistan’s boats are restricted to days underwater, further eroding the credibility of its retaliatory threat.

A Stark Contrast: India’s Advancing Undersea Force

India, by contrast, has made significant strides in strengthening its undersea deterrent. The Indian Navy’s operational fleet includes the Arihant-class nuclear-powered ballistic missile submarines (SSBNs), which provide a credible second-strike capability and can remain deployed for extended periods. In addition, India is advancing its indigenous submarine programmes, with new Scorpene-class boats entering service and the ambitious Project-75I set to deliver next-generation submarines equipped with advanced propulsion and weapon systems. This focus on indigenous development and nuclear propulsion stands in sharp contrast to Pakistan’s ongoing struggles with foreign-supplied, conventionally powered platforms.

Operation Sindoor has deepened doubts about the Pakistan Navy’s undersea deterrence, exposing a crisis marked by operational paralysis, delayed modernisation, and strategic overdependence on external partners.