Turkey has entered a decisive new phase in its naval modernisation with the commissioning of TCG Hızırreis (S-331), the second submarine in the cutting-edge Reis-class fleet. The ceremony at Gölcük Naval Shipyard marks a watershed moment in Ankara’s maritime strategy at a time of accelerating geopolitical tensions in the Eastern Mediterranean and Black Sea.
The handover of TCG Hızırreis represents far more than an expansion of force structure. It confirms Turkey’s determination to strengthen its A2/AD (anti-access/area-denial) posture across contested waters shaped by energy rivalries, exclusive economic zone (EEZ) disputes, and growing great-power competition. With the region’s undersea domain becoming increasingly crowded and strategically vital, Ankara is positioning itself to secure long-term leverage beneath the waves.
The commissioning of TCG Hızırreis comes just over a year after the Navy inducted the lead vessel, TCG Piri Reis (S-330), in August 2024. Together, the two air-independent propulsion (AIP) submarines give Turkey a new asymmetric advantage: long-endurance covert operations without surfacing, making them exceptionally difficult for adversaries to detect.
The submarine was delivered through close cooperation between Germany’s ThyssenKrupp Marine Systems (TKMS) and Turkey’s Gölcük Naval Shipyard, a partnership that has gradually shifted integration expertise, systems management, and industrial capabilities into Turkish hands. The project is a central pillar of Turkey’s defence industrial evolution, contributing to Ankara’s broader ambition of advancing naval autonomy.
Valued at €2.06 billion (approximately USD 2.24 billion), the six-boat Reis-class programme is a cornerstone of Turkey’s “Blue Homeland” (Mavi Vatan) doctrine, which emphasises maritime sovereignty, sea-lane protection, and resource security across the Aegean, Mediterranean, and Black Sea.
Turkey’s submarine fleet has historically relied on German-built Type 209 diesel-electric boats, including the 209/1200 and Preveze-class 209/1400 variants. These platforms have been reliable but are now outpaced by the AIP-equipped submarines fielded by Greece, Israel, and other regional powers.
The transition to the Reis-class—based on the Type 214 design—marks a generational leap. Turkey selected the design through a competitive tender in 2008, choosing TKMS over France’s DCNS and Spain’s Navantia due to proven AIP performance and greater modularity.
The programme officially launched in 2011, with the keel of TCG Piri Reis laid in 2015. Its launch in 2019 signalled Ankara’s intent to accelerate naval modernisation, a pace maintained through the launches and sea trials of subsequent vessels. TCG Murat Reis (S-332) is currently in the outfitting phase, while other units progress through production.
The naming of the submarines—Piri Reis, Hızırreis, Murat Reis, Aydın Reis, Seydi Ali Reis, and Selman Reis—reflects Turkey’s national maritime heritage and honours legendary Ottoman naval commanders.
The Type 214TN submarines are designed for survivability and lethality in contested environments. At 68 metres long with a submerged displacement of over 2,000 tonnes, each submarine carries a crew of around 40 and is optimised for long-duration missions.
The defining feature is the hydrogen fuel-cell AIP system, allowing the submarine to remain submerged for up to three weeks, drastically reducing exposure to enemy detection systems. Its propulsion combines a highly silent Siemens Permasyn motor with MTU diesel engines for surfaced running, giving it submerged speeds exceeding 20 knots.
The hull features advanced acoustic-dampening coatings, minimising sonar reflections and making the platform one of the stealthiest in the region.
Eight 533mm torpedo tubes
DM2A4 Seehecht heavyweight torpedoes
Turkey’s indigenous Akya torpedo
Sub-Harpoon anti-ship missiles
Future integration of the submarine-launched variant of Turkey’s Atmaca missile
The potential future integration of land-attack cruise missiles could transform the submarine into a strategic deep-strike asset.
The vessel’s sensors include next-generation periscopes by Aselsan, sonar arrays by Atlas Elektronik, and an advanced electronic warfare suite. A Havelsan-integrated combat management system enables real-time data fusion and allows the submarine to function as part of a networked naval force, coordinating with unmanned surface and underwater vehicles.
The arrival of TCG Hızırreis comes at a time of heightened maritime friction. In the Eastern Mediterranean, Turkey’s disputes with Greece and Cyprus over EEZ boundaries and hydrocarbon exploration have intensified. The ability to deploy AIP submarines for extended stealth patrols gives Ankara a significant deterrent edge and complicates NATO and EU naval planning.
During the 2020 Oruç Reis crisis, Turkey recognised the strategic importance of undersea presence to protect exploration activities. The Reis-class directly addresses the shortcomings observed during that period, making Turkey’s submarine patrols both more persistent and more difficult to track.
In the Black Sea, Russia’s war in Ukraine has transformed the maritime environment. Turkey’s control of the Turkish Straits under the Montreux Convention already gives it major geopolitical leverage, but AIP submarines enhance its capacity to monitor Russian naval movements while strategically avoiding direct confrontation.
Admiral Ercüment Tatlıoğlu, Commander of the Turkish Navy, emphasised that the Reis-class will contribute to “long-term submarine deterrence capability,” signalling Turkey’s intent to sustain influence across multiple maritime theatres.
Turkey’s defence industry has rapidly expanded, with exports surpassing USD 6.3 billion in 2024. Companies such as STM, Aselsan, Roketsan, Havelsan, and Baykar now play central roles in the country’s military transformation.
The Reis-class submarines showcase Turkey’s ability to integrate indigenous systems into German-origin platforms, strengthening strategic autonomy and creating pathways for possible exports. Ankara could target Asian, Middle Eastern, or African markets with lower-cost alternatives to European or South Korean submarines.
Turkey’s maritime expansion is complemented by other high-profile defence products, including MILGEM corvettes exported to Pakistan and T129 ATAK helicopters sold to the Philippines.
The Reis-class is a stepping stone toward Turkey’s long-term ambition of designing and producing its own submarines under the MILDEN (Milli Denizaltı) programme. Construction began in January 2025, with Turkey aiming to field fully indigenous AIP-equipped submarines by the early 2030s. These may incorporate next-generation technologies such as advanced lithium-ion batteries or hybrid propulsion.
Admiral Tatlıoğlu has also expressed Turkey’s aspirations to eventually acquire nuclear-powered submarines, which would elevate the Turkish Navy to an elite tier of global naval capabilities.
Turkey’s rapid naval expansion has prompted responses from regional rivals. Greece is accelerating upgrades to its Papanikolis-class submarines and purchasing new frigates, while Israel and Egypt continue strengthening their fleets with Western platforms.
Operational challenges persist as well, especially in the shallow and geographically complex Aegean Sea, where submarine manoeuvrability, crew training, and situational awareness are critical. Turkey has increased investment in submarine simulators and conducted joint exercises with Pakistan to enhance proficiency.
The commissioning of TCG Hızırreis marks a pivotal milestone in Turkey’s transformation into a formidable undersea power. By combining imported precision engineering with growing indigenous innovation, Turkey is rapidly evolving from a regional maritime actor into a strategically influential naval force.
With unmatched endurance, stealth, and combat versatility, the Reis-class strengthens Turkey’s ability to safeguard maritime interests in some of the world’s most volatile waters. As the MILDEN programme matures and Ankara moves toward nuclear submarine aspirations, the Turkish Navy’s future may extend far beyond regional deterrence—toward a role as a global maritime stakeholder.
