The Type 212A is a class of diesel-electric submarine developed by Howaldtswerke-Deutsche Werft AG (HDW) for the German Navy (German: U-Boot-Klasse 212 A), and the Italian Navy where it is known as the Todaro class. It features diesel propulsion and an additional air-independent propulsion (AIP) system using Siemens proton-exchange membrane (PEM) compressed hydrogen fuel cells. The submarines can operate at high speed on diesel power or switch to the AIP system for silent slow cruising, staying submerged for up to three weeks with little exhaust heat. The system is also said to be vibration-free and virtually undetectable.
The Type 212 is the first fuel cell propulsion system equipped submarine series.
In April 2006, the German Navy's U-32 sailed from the Baltic Sea to Rota, Spain in a journey lasting two weeks which covered 1,500 nautical miles (2,800 km; 1,700 mi) without surfacing or snorkelling.
The Italian Navy's S 526 Todaro was deployed, for over six months in 2008, to the United States for CONUS 2008 exercise with the United States Navy.
The Italian Navy's S 527 Scirè was deployed, for over five months in 2009, to the U.S. for CONUS 2009 exercise with the United States Navy.
The Italian Navy's S 526 Todaro, between 1 September 2012 and 13 February 2013, for the first time was deployed to the Gulf of Aden, Arabian Sea, Gulf of Oman and the Indian Ocean.
In 2013, while on the way to participate in naval exercises in U.S. waters, the German Navy's U-32 established a new record for non-nuclear submarines with 18 days in submerged transit without snorkelling.
On 15 October 2017, the German Navy's U-35 suffered damage to its rudder fins while conducting dives off the Norwegian coast