India's INS Aridhaman SSBN Commissioned, Boosting Nuclear Triad

India commissioned the Arihant‑class nuclear‑powered ballistic missile submarine INS Aridhaman on 3 April 2026 at Visakhapatnam. The stretched hull carries eight vertical launch tubes and is equipped to fire the indigenous K‑4 SLBM with a 3,500 km range, doubling the strike capacity of earlier boats. Its 83 MW pressurised‑light‑water reactor offers higher power density and a reduced acoustic signature, making it the quietest Indian submarine to date.

The addition of a third operational SSBN allows the Indian Navy and Strategic Forces Command to rotate one submarine on continuous at‑sea deterrent patrol, one on high‑readiness transit, and one in maintenance, moving toward a credible Continuous At‑Sea Deterrent (CASD). Full CASD capability, however, will require the forthcoming S5‑class boats.

The commissioning coincides with the near‑completion of the underground INS Varsha base, designed to house up to 12 nuclear submarines and shield them from satellite surveillance. While the new SSBN strengthens India’s second‑strike posture against regional rivals, particularly China, India still lacks indigenous nuclear attack submarines and continues to lease Russian vessels until the mid‑2030s.