Singapore Orders Two More Type 218SG Submarines from Germany’s tkMS to Bolster Naval Power.

On May 7, 2025, thyssenkrupp Marine Systems (tkMS), a leading German naval shipbuilder, signed a new contract with Singapore’s Defence Science and Technology Agency (DSTA) for the construction of two additional Type 218SG submarines. This significant development strengthens the long-standing naval partnership between Germany and Singapore, expanding the Republic of Singapore Navy’s (RSN) Type 218SG fleet from four to six units, and underlining Singapore’s growing emphasis on undersea warfare capabilities.
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RSS Impeccable, one of Singapore Navy's German-built Type 218SG submarines, during its commissioning ceremony. (Picture source: Singapore Navy)

Based in Kiel, northern Germany, thyssenkrupp Marine Systems is a subsidiary of the German industrial conglomerate thyssenkrupp AG. The company is internationally recognized as one of the foremost developers of advanced non-nuclear submarines and naval surface combatants, with a proven track record of delivering highly customized and technologically sophisticated vessels to navies worldwide.

The latest acquisition reflects Singapore’s strategic commitment to maintaining a modern, stealth-capable submarine force amid intensifying maritime security challenges in the Asia-Pacific region. With critical sea lines of communication passing through Southeast Asian waters and increasing military activity in contested areas such as the South China Sea, Singapore recognizes the need for persistent, survivable, and adaptable undersea deterrence.

Currently, the RSN operates a submarine fleet comprising four conventional diesel-electric submarines (SSKs): two Archer-class and two Type 218SG submarines. The Archer-class boats, formerly the Swedish Navy’s Västergötland-class, were acquired and extensively modernized by Singapore. These vessels are equipped with air-independent propulsion (AIP) using Stirling engines, and armed with three 400mm torpedo tubes for the Torped 431 lightweight torpedo, along with six 533mm tubes firing Black Shark heavyweight torpedoes.

The centerpiece of Singapore’s submarine modernization is the German-built Type 218SG class, with RSS Invincible and RSS Impeccable already in active service. These submarines were custom-designed by tkMS to meet Singapore’s operational needs in both deep and shallow littoral waters. Derived from the German Type 214 platform, the Type 218SG includes substantial enhancements, particularly in stealth, endurance, and combat systems integration.

Each Type 218SG submarine is fitted with eight single 533mm torpedo tubes capable of launching the advanced Black Shark heavyweight torpedo, offering a powerful anti-submarine and anti-surface warfare capability. The submarines can also deploy naval mines and are equipped for launching special operations or unmanned underwater vehicles, expanding their versatility in intelligence, surveillance, and reconnaissance (ISR) missions.

A defining feature of the Type 218SG is its cutting-edge AIP system based on fuel-cell technology, which enables extended submerged endurance without the need to surface or snorkel, dramatically increasing its operational stealth and survivability. The pressure hull and hydrodynamic profile are optimized for quiet operations in warm, noisy, shallow waters—typical of Southeast Asia’s maritime geography.

Internally, the submarines are equipped with a state-of-the-art combat management system developed jointly by DSTA and international partners, integrating a comprehensive suite of sonar systems including flank arrays, passive and active sonar, and a towed array. These allow the submarines to detect, classify, and track enemy vessels at long range and in acoustically complex environments.

This expansion comes at a time when tkMS is experiencing unprecedented demand across the naval sector, with an order book valued at approximately €16 billion. The two additional submarines for Singapore will be built in Germany using existing shipyard capacity in Kiel, even as the company fulfills other large-scale contracts, including four additional Type 212CD submarines for the German Navy and the new Polarstern icebreaker.

Beyond the immediate operational benefits, the acquisition signals Singapore’s broader strategic objectives. Submarines provide the RSN with a powerful deterrent and a flexible response option in times of crisis. They can silently monitor adversary movements, disrupt enemy supply lines, and project power covertly. In an era of multi-domain threats and great power competition, the ability to remain undetected and strike with precision is increasingly valued.

With the addition of these two new Type 218SG submarines, Singapore is poised to operate one of the most advanced and capable non-nuclear submarine fleets in Asia by the 2030s. This force expansion will not only strengthen Singapore’s maritime defense posture but also contribute to regional stability through deterrence, interoperability, and the ability to participate in complex multinational naval operations.

The decision to deepen its investment in submarine warfare reflects a clear vision: Singapore is positioning itself as a high-tech naval power capable of safeguarding its interests beneath the waves in one of the world’s most strategically contested maritime regions.