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India nears sea-based nuclear triad as K-4 missile clears key test

DRDO tested the K-4 missile, launched from Indian nuclear powered ballistic missile (SSBN) INS Arighaat, in the Bay of Bengal on December 23.

Published on: Dec 25, 2025, 16:33:50 IST
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India is set for the final operational validation of its sea-based nuclear triad with its 3500-km-range K-4 submarine launched nuclear ballistic missile requiring a few more test-firings before being inducted into the country’s nuclear arsenal operated by tri-services Strategic Forces Command (SFC). DRDO tested the K-4 missile, launched from Indian nuclear powered ballistic missile (SSBN) INS Arighaat, in the Bay of Bengal on December 23.

The K-4 missile requires a couple of more test-firings before induction. (Photo from X)
The K-4 missile requires a couple of more test-firings before induction. (Photo from X)

While the Modi government normally does not speak about the country’s nuclear platforms and missiles, HT learns that the test-firing of K-4 missiles was delayed from the previous schedule of December 1-3 as a Chinese Ocean Mineral Resources Vessel was sighted 115 nautical miles on the southern edge of the navigation area on December 3. This Chinese vessel, however, did not have any missile tracking equipment on-board.

Although Chinese research vessels “ Shi Yan 6, Shen Yi Hao and Lan Hai” were present in the Indian Ocean Region last month, a Luyang III destroyer (the only one currently), a Jiangkai II frigate and a Fuchi class tanker, all part of the 48th anti-piracy escort force, were off the Gulf of Aden.

Even though the K-4 missile requires a couple of more test-firings before induction, India is all set to commission INS Aridhaman, the third SSBN in Arihant class, in the first quarter of 2026. On October 16, Defence Minister Rajnath Singh launched S4*, the last of Arihant class SSBNs, which may be commissioned in the Indian SFC towards the end of decade. Barring INS Arihant, which carries on 750-km range K-15 nuclear missiles, all others in this class carry K-4 missiles. The next class of SSBNs will be around 10,000 tonnes and will carry K-5 missiles with a range more than 5,000km.

In the meantime, India has signed on to acquire the Akula class nuclear powered conventionally armed attack submarine (SSN) from Russia latest by 2028. While Russia has recently offered India another SSN on lease, the Modi government has cleared the Indian Navy’s plan to construct two SSNs under “Make in India” on October 9. The SSNs hold advantage over diesel powered attack submarines (SSKs) as they have unlimited range and are constrained only by food supplies, crew fatigue and maintenance. The SSNs carry more torpedoes and missiles and do not have to surface for charging batteries. The only advantage of SSKs is that they are very quiet as compared to SSNs and SSBNs and can be used for surprise attacks .

At present China and Turkey are supplying guided missiles frigates to Pakistan with Turkey upgrading Islamabad’s submarines and Beijing supplying new Yuan class submarines. Under the circumstances, India has strategic threats both in Arabian Sea as well as the larger Indian Ocean Region with Chinese aircraft carrier led patrols expected in 2026 after the commissioning of the latest Fujian heavy carrier. The Chinese carrier based pilots and platforms have also shown rapid learning skills and pose a threat to the Indo-Pacific. The only counter to surface threats in the Indian Ocean Region are Indian SSBNs and SSNs as onlya sea based deterrent has survivability and second-strike capability.

  • Shishir Gupta
    ABOUT THE AUTHOR
    Shishir Gupta

    Shishir Gupta is Executive Editor at Hindustan Times and one of India's top journalists covering national security, strategic affairs, foreign policy and geopolitics. Over the past three decades, he has extensively reported on India's military, diplomatic and security landscape, covering every major conflict and national security challenge, from the 1999 Kargil War and the 2020 East Ladakh standoff to Operation Sindoor in 2025. He has also covered major terror attacks, including the IC-814 hijacking, the 26/11 Mumbai attacks and the 2025 Pahalgam terror strike, along with numerous Pakistan-backed terrorist incidents in the Kashmir Valley and across India. He has reported on national and state elections for more than three decades. A recognised authority on strategic affairs, Gupta has covered India's nuclear programme since the Pokhran-II (Shakti series) tests in May 1998 and has written extensively on global nuclear issues, Indian diplomacy and the country's expanding global outreach. He has also reported widely on international conflicts and terrorism, with a special focus on the Indian subcontinent. Gupta has interviewed Prime Minister Narendra Modi more than four times, including Modi's first interview with the print media after becoming Prime Minister in May 2014. His other interviews include three with the Dalai Lama, as well as conversations with Benjamin Netanyahu, Amit Shah, Yogi Adityanath, S. Jaishankar, Nirmala Sitharaman and Piyush Goyal. He is the author of Indian Mujahideen: The Enemy Within (Hachette, 2011) and Himalayan Face-off: Chinese Assertion and Indian Riposte (Hachette, 2014). He was awarded the Chevening-Wolfson Joint Scholarship at Wolfson College, University of Cambridge, UK, in 1998 and participated in the International Visitor Leadership Program (IVLP) of the US State Department in 2006. He received the Ben Gurion Prize from Israel in 2011 and the K. Subrahmanyam Prize for Strategic Studies in 2015 from the Manohar Parrikar Institute for Defence Studies and Analyses (MP-IDSA). Since 2024, he has hosted Point Blank, Hindustan Times' weekly YouTube show on global geopolitics.Read More

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