Explained
Pakistan acquires Hangor-class submarines from China:Plans Bay of Bengal deployment for 1st time since 1971 war; can it be done? What laws say
7 hours agoAuthor: Akriti Saxena
Fifty-five years after a Pakistani submarine sank the only Indian warship ever lost in combat, a new fleet bearing the same name is preparing to enter the same waters. The stakes this time are considerably higher.
Pakistan has inducted the first of its eight Chinese-built Hangor-class submarines and signalled its intention to deploy them in the Bay of Bengal, a region where Islamabad has had virtually no naval presence since the 1971 war that created Bangladesh.
The move is the centrepiece of Pakistan's most ambitious naval modernisation programme in decades, and it is unfolding at a moment when the strategic geography of the Indian Ocean is shifting in ways that New Delhi cannot afford to ignore.
What are Hangor-Class submarines?
In 2015, Pakistan signed a $5 billion deal with China for eight diesel-electric attack submarines, at the time, the largest arms export contract in Chinese military history.
Four are being built at the Wuchang Shipbuilding Industry Group in Wuhan; the remaining four will be assembled at Karachi Shipyard under a technology transfer arrangement that also builds Pakistan's domestic submarine manufacturing capacity.
The first vessel, PNS Hangor, was commissioned in Sanya, China, in April 2026 and has since arrived in Karachi. All eight are expected in service by 2028.
The submarines are export derivatives of China's Type 039A/B Yuan-class, the same design family that forms the backbone of the People's Liberation Army Navy's own conventional submarine fleet.
Pakistan had purchased the advanced diesel-electric submarine PNS Hangor from France. Because of its modern technology, it was referred to as a ‘shark’
What are their specifications and capabilities?
The defining capability of the Hangor-class is its Air Independent Propulsion system, or AIP. Conventional diesel-electric submarines must periodically surface, or at a minimum raise a snorkel, to run diesel engines and recharge batteries.
Each time they do, they risk acoustic or radar detection. AIP eliminates that vulnerability by generating power through a Stirling engine chemical reaction, without combustion and without surfacing.
The Hangor-class can remain submerged for up to 15–20 days on AIP alone, moving near-silently at patrol depth.
The name is not accidental: 1971 and the ghost of INS Khukri
To understand why the name Hangor carries such weight, it is necessary to go back to the night of 9 December 1971.
The Indian frigate INS Khukri was hunting a Pakistani submarine off the coast of Diu in the Arabian Sea when the tables turned. PNS Hangor, a French-built Daphn├й-class submarine under Commander Ahmed Tasnim, locked onto the frigate's sonar signature and fired.
The torpedo struck Khukri beneath her oil tanks. She sank in under two minutes, taking 176 sailors and her captain, Mahendra Nath Mulla, down with her.
INS Khukri was part of the Indian Navy’s 14th Squadron. Britain had provided this outdated ship as a gesture to repay its debt to Indian soldiers who took part in the Second World War
It was the first time a submarine had sunk a warship anywhere in the world since the Second World War. It remains the only Indian Navy warship ever lost in combat since Independence.
Pakistan lost the 1971 war decisively. Bangladesh was born from the wreckage of its eastern province.
But the Hangor episode endured in Pakistani naval memory as proof that a single well-deployed submarine could impose disproportionate strategic costs on a larger adversary, forcing India to commit an entire carrier battle group to a four-day anti-submarine hunt that ultimately failed to sink the vessel.
By naming its newest submarine class Hangor, Pakistan is not merely invoking history. It is issuing a doctrinal statement.
How could their deployment reshape South Asia's defence equations?
Retired Brigadier Hemant Mahajan, a defence analyst who has written extensively on South Asian maritime security, says the Hangor deployment would not immediately alter the regional balance of power, but it would add significant friction to India's strategic calculations.
The most immediate effect is what Mahajan calls a two-front maritime challenge. India's Navy already tracks Chinese submarines and research vessels in the Bay of Bengal and the Andaman Sea.
Pakistani AIP submarines in the same waters would add another near-silent, hard-to-detect presence, requiring more P-8I maritime patrol aircraft sorties, additional ASW helicopters, expanded seabed sensor networks, and greater operational readiness around the Andaman and Nicobar Islands.
The deeper concern is geometric. India's Arihant-class nuclear submarines, the sea-based leg of its nuclear deterrent, are most likely patrolled from the northern Bay of Bengal.
Their patrol zones are relatively predictable, constrained by missile range requirements. A Pakistani submarine operating in those waters, even occasionally, introduces an ASW burden on India's eastern flank at precisely the moment its assets are already stretched westward across the Arabian Sea.
Mahajan is careful to frame the Hangor's primary role as sea denial rather than sea control. "They can complicate Indian naval operations, threaten shipping routes and increase surveillance capabilities," he says, "but they do not provide Pakistan with naval parity with India." The Hangor fleet's purpose is to raise the cost of Indian presence operations, not to win an underwater war it cannot win.
The broader architecture surrounding the Hangor compounds this picture. China's PLA-affiliated Poly Technologies has built submarine infrastructure at Chittagong. Beijing controls Hambantota port in Sri Lanka and is expanding repair and sustainment capacity at Gwadar in Pakistan.
The Hangor fleet is not a standalone development, it is one node in a Chinese-anchored arc of maritime influence stretching from Gwadar through Hambantota to Chittagong, designed to give Beijing persistent Indian Ocean access without requiring Chinese vessels to be in every theatre simultaneously.
Can Pakistan legally do this?
Yes, and the legal framework here matters as much as the strategic one.
Under the United Nations Convention on the Law of the Sea, or UNCLOS, all states enjoy freedom of navigation on the high seas. Pakistan requires no one's permission to deploy submarines in international waters of the Bay of Bengal, just as India, China, and the United States routinely operate naval vessels across each other's near waters.
The rules change at the coastline. Within a country's territorial sea, the 12-nautical-mile zone from its baseline, foreign submarines must surface, show their flag, and comply with innocent passage rules. Operating submerged through another country's territorial waters is a violation of international law.
Beyond 12 nautical miles, however, including within a country's 200-nautical-mile Exclusive Economic Zone, submerged transit is legally permitted. Coastal states have sovereign rights over resources in their EEZ, but not over the movement of foreign military vessels.
What Pakistan cannot do without Bangladesh's explicit consent is use Bangladeshi ports, Chattogram, Payra, Matarbari, for replenishment, crew rotation or maintenance. That distinction is operationally critical.
What does this mean for India and Bangladesh?
Pakistan's Bay of Bengal ambitions are inseparable from what has happened in Bangladesh since August 2024, when Sheikh Hasina's government fell. Hasina had maintained close strategic ties with New Delhi for over a decade. Her removal produced an immediate recalibration in Dhaka.
Under Muhammad Yunus's interim government, Bangladesh began diversifying its strategic partnerships toward Pakistan, China, Turkey and Gulf states. In November 2025, Pakistan Navy frigate PNS Saif docked at Chattogram, the first Pakistani warship to enter Bangladeshi waters since 1971.
Pakistan's naval chief visited Dhaka the same week. Bangladeshi Air Force officials subsequently expressed interest in acquiring JF-17 fighter jets, a Chinese-Pakistani co-production.
Mahajan believes this opens both a risk and an opportunity for India. The risk is that Chattogram, Payra and Matarbari, ports already contested between Indian and Chinese interests, could gradually become more accessible to Pakistani and Chinese naval activity. "India is likely to become more sensitive to any foreign naval access arrangements that could facilitate Chinese or Pakistani submarine operations in the Bay," he says.
The opportunity, Mahajan argues, is that a Pakistani submarine presence in the Bay of Bengal also gives India a concrete security proposition to offer Bangladesh. A submarine operating in waters that overlap with Bangladesh's fishing grounds, offshore energy fields and commercial shipping routes is a shared concern, not only an Indian one.
"India can position itself as Bangladesh's primary partner for maritime domain awareness, intelligence sharing and coordinated maritime security," he says, offering coast guard platforms, hydrographic support and EEZ surveillance technology as instruments of alignment.
The challenge is calibration. Dhaka is unlikely to abandon its hedging strategy, it will continue balancing India, China and Pakistan to extract maximum benefit from each. Pushing Bangladesh publicly into an anti-Pakistan posture risks driving it further toward Beijing. India's response, Mahajan suggests, must be practical cooperation rather than political pressure.
