Singapore Signs Contract For Two More Invincible-Class Submarines

The Ministry of Defence of Singapore has signed a contract with Germany’s thyssenkrupp Marine Systems (TKMS) to acquire two more Invincible-class submarines, expanding the Republic of Singapore Navy (RSN)’s future submarine fleet to six units.

The deal follows an announcement made by Singapore’s Minister for Defence, Dr. Ng Eng Hen, during the Committee of Supply debate in Parliament in March 2025. Dr. Ng had revealed that the RSN planned to increase its submarine strength beyond the four Invincible-class submarines already in the pipeline.

These submarines are part of Singapore’s long-term naval development programme and are customised by the Defence Science and Technology Agency (DSTA) to meet Singapore’s specific operational needs. The Invincible-class submarines are designed for shallow, busy tropical waters and can operate with a lean crew of 28.

According to the Ministry of Defence, the new submarines are expected to be delivered from 2034 as part of the RSN’s submarine force renewal programme.

The first two submarines of the class, RSS Invincible and RSS Impeccable, were commissioned in September 2024. Trials and acceptance activities for the third and fourth submarines, RSS Illustrious and RSS Inimitable, are ongoing in Germany, with their delivery to Singapore expected by 2028.

The Invincible-class (also known as Type 218SG) submarines are variants of the TKMS Type 214 model, incorporating features from the Type 212A, including the distinctive X-shaped rudder section. Displacing 2,200 tonnes submerged, they measure 70 meters in length and 6.3 meters in diameter. These submarines are fitted with an Air Independent Propulsion (AIP) system based on fuel cell technology, allowing them to remain submerged about 50% longer compared to conventional diesel-electric submarines.

The submarines carry a combat system co-developed by Atlas Elektronik and Singapore’s ST Electronics. Their armament is launched from eight 533mm torpedo tubes and includes torpedoes, naval mines, and anti-ship missiles. The design also features a Horizontal Multi-Purpose Lock (HMPL) for launching special forces or deploying additional equipment, further enhancing the boats’ mission flexibility.