India’s fourth ballistic missile submarine (SSBN), S4*, has commenced sea trials and achieved a historic 80% indigenous content, marking a significant milestone in the nation’s quest for self-reliance in defense. This advanced platform, an iteration of the Arihant-class, boasts enhancements including a larger weapons payload and improved system integration, reducing dependence on foreign imports. The upcoming S5 SSBNs aim for over 90% indigenization, while Project-77 targets 95% for nuclear-powered attack submarines, underscoring India’s strategic pivot towards total sovereignty in underwater warfare technology. These developments not only bolster India’s nuclear deterrent capabilities but also position it as a formidable player within the Indo-Pacific geopolitical landscape.