The Indian Navy's endeavor to acquire advanced fuel cell-based Air Independent Propulsion (AIP)-equipped submarines is making progress, with evaluations of offerings from Germany and Spain. Navantia from Spain is field-testing its AIP technology on the S80 submarine, utilizing hydrogen produced from bioethanol, enhancing energy reserves and operational stealth. This technology aligns closely with India's requirements for the P75I project, providing a potential solution without the need for major redesigns. On the other hand, ThyssenKrupp from Germany is presenting 214-class submarines tailored to Indian Navy specifications, incorporating cutting-edge AIP advancements, including hydrogen fuel cells for extended submergence periods and heightened stealth capabilities. Both submarine options feature Lithium-ion batteries alongside fuel cell AIP systems, enabling prolonged endurance and rapid maneuverability. The AIP technology's ability to operate quietly and launch torpedoes stealthily, combined with reduced acoustic and thermal signatures, enhances the overall stealth of these submarines, crucial for naval defense operations. The submarines are designed to be 'game changers' in the Indian Navy's fleet, offering state-of-the-art sensor suites, combat systems, and stealth features to bolster the country's naval capabilities and modernization efforts.