India has successfully tested the K-4 submarine-launched ballistic missile (SLBM) from the INS Arighaat in the Bay of Bengal, marking a significant enhancement to its naval nuclear capabilities. This missile, with a range of approximately 3,500 kilometers, allows Indian nuclear-powered ballistic missile submarines (SSBNs) to target deep within adversarial territories while remaining in secure waters, thus bolstering India’s second-strike capability in alignment with its no-first-use doctrine. The K-4’s capabilities surpass those of its predecessor, the K-15, which had a limited range, compelling Indian submarines to approach dangerous waters for effective deterrence. The successful test signals a critical advancement in India’s sea-based nuclear deterrent, reflecting an ongoing effort to enhance the operational readiness and strategic flexibility of its underwater forces, particularly against regional threats in the Indo-Pacific. As India continues to develop its underwater capabilities, including the upcoming Arihant-class submarines and the anticipated S-5 class, the nation strengthens its position as a formidable maritime power, emphasizing the importance of maintaining credible deterrence amid evolving geopolitical dynamics.