India has taken a decisive step to enhance its naval capabilities with the approval of a ₹70,000 crore (approximately $8.2 billion) deal under Project 75 India (P-75I). This ambitious defense project will see the construction of six advanced diesel-electric stealth submarines equipped with Air Independent Propulsion (AIP) technology. The submarines will be built by Mazagon Dock Shipbuilders Limited (MDL) in collaboration with ThyssenKrupp Marine Systems (TKMS), a German defense leader known for its proven submarine technology. The project is not only a strategic boost for the Indian Navy but also a major push for the Make in India initiative.

Overview of Project 75 India (P-75I)

Project 75I is part of India’s long-term naval modernization plan aimed at countering growing regional threats. It builds on the earlier Project 75 that delivered six Scorpene-class (Kalvari-class) submarines. The new project focuses on acquiring six next-generation submarines with advanced stealth, endurance, and combat capabilities. Originally conceptualized in 1997, it faced years of delays due to procurement hurdles and technical disputes. The approval on August 23, 2025, is therefore seen as a breakthrough in strengthening India’s underwater warfare capabilities.

The objectives of P-75I include enhancing operational readiness in the Indo-Pacific, countering the growing naval presence of China and Pakistan, advancing indigenous defense manufacturing under Atmanirbhar Bharat, and developing submarine-building expertise to position India as a future hub for global submarine production.

India-Germany Partnership: MDL and TKMS

The six submarines will be built in India by MDL with technological support from TKMS. MDL has already delivered six Scorpene-class submarines and brings proven expertise in submarine construction. TKMS, on the other hand, is recognized globally for its Type 214 submarines, which are used by navies in Germany, Greece, South Korea, and Turkey.

The MDL-TKMS consortium emerged as the sole bidder after the rival group of Larsen & Toubro and Spain’s Navantia was disqualified due to the unproven status of Navantia’s AIP system. Key aspects of the partnership include advanced technology transfer from TKMS, significant indigenous manufacturing with local content starting at 45 percent for the first submarine and rising to 60 percent by the sixth, and the use of a reliable hydrogen fuel cell-based AIP system for superior operational performance.

Strategic Importance of the Deal

The Indian Navy currently operates 16 conventional submarines, but nearly 10 of them are expected to retire in the next decade. With China already operating over 60 submarines and Pakistan modernizing its fleet with Chinese assistance, India urgently needs replacements to maintain its undersea advantage. The new submarines under P-75I will help protect vital sea lanes in the Indian Ocean, conduct both defensive and offensive missions, and provide intelligence, surveillance, and reconnaissance (ISR) support.

The deal also complements India’s other naval modernization efforts, including plans to build nuclear-powered attack submarines with Larsen & Toubro and the ongoing ₹35,000 crore project for three additional Scorpene-class submarines with France’s Naval Group.

The Game-Changer: AIP Technology

The most significant feature of these submarines is their Air Independent Propulsion system. Unlike traditional diesel-electric submarines that must surface or use a snorkel every few days to recharge batteries, AIP-equipped submarines can stay submerged for up to three weeks. This makes them extremely difficult to detect.

TKMS’s hydrogen fuel cell-based AIP system works by generating electricity from hydrogen and oxygen with minimal noise, vibration, and heat. Compared to Sweden’s Stirling engine or France’s closed-cycle diesel systems, it is quieter and more efficient. Navantia’s bio-ethanol-based AIP system was rejected as unproven, while India’s DRDO is also developing its own indigenous AIP system for future integration.

Features and Capabilities

The P-75I submarines, based on an evolved Type 214 design, will have a displacement of around 3,000 tonnes, making them larger than the Scorpene-class. They will be equipped with 18 heavyweight torpedoes, 12 land-attack cruise missiles, and advanced anti-ship missiles. With cutting-edge sonar, electronic warfare systems, and a modern combat management system, these submarines will support multiple mission profiles including anti-submarine warfare, anti-surface warfare, land-attack operations, and special missions.

Timeline and Cost

The Cabinet Committee on Security cleared the project on August 23, 2025. Negotiations between the Defence Ministry, MDL, and TKMS are expected to conclude within six to eight months, with the contract signing targeted for early 2026. The first submarine is projected to be delivered by 2032–2033, although some reports suggest a faster three-to-five-year timeline may be attempted. The estimated cost is ₹70,000 crore, higher than the earlier ₹43,000 crore estimate due to inflation and additional Navy requirements.

Economic and Industrial Impact

A cornerstone of the deal is its alignment with the Make in India program. Indigenous content will rise from 45 percent to 60 percent across the six submarines, providing a major boost to India’s defense industry and MSME sector. The project will generate jobs, promote technology transfer, and enhance India’s long-term submarine-building expertise, laying the foundation for future indigenous projects like Project 76.

TKMS has also shown interest in using India as a base for submarine exports, which could position the country as a global hub for submarine manufacturing.

Challenges and Concerns

Despite its promise, Project 75I faces hurdles. Delays have already pushed the project back by over a decade. The single-bidder situation raises concerns about reduced cost competition. Integration risks with DRDO’s indigenous AIP system could also cause setbacks, and timely delivery will be critical to prevent a capability gap as older submarines retire.

Strategic and Geopolitical Implications

The deal will significantly strengthen India’s maritime posture in the Indo-Pacific, enhancing deterrence against both China and Pakistan. The submarines’ stealth and strike capabilities will allow India to project power and secure vital trade routes. It also strengthens Indo-German defense ties, building on earlier agreements and Germany’s recent policy shift towards deeper engagement with India in the Indo-Pacific.

Conclusion

The India-Germany submarine deal under Project 75I is one of the most significant defense contracts in India’s history. By combining German technology with Indian shipbuilding, the project will deliver six state-of-the-art submarines that drastically improve India’s underwater combat capabilities. With advanced AIP systems, long endurance, and powerful weaponry, these submarines will be game-changers in the Indo-Pacific theater. 

The project’s emphasis on Make in India and indigenous content also ensures that the benefits extend beyond defense into economic and technological growth. While challenges remain, the successful execution of Project 75I will mark a turning point in India’s naval power and its quest for maritime dominance.