The R-class or Romolo-class submarine was a group of submarines built for the Royal Italian Navy (Regia Marina Italiana) during World War II. They were designed as blockade running transport submarines for transporting high-value cargo from Europe to Japan and vice versa. Axis-occupied Europe lacked strategic materials such as tungsten, tin and some commodities such as rubber.
The R-class submarines displaced surfaced and submerged. The submarines were long, had a beam of and a draft of . They had a cargo capacity of .
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the R class had a range of at ; submerged, they had a range of at .
The boats were only armed for self-defense with three light anti-aircraft guns. Some boats may have been equipped with a pair of internal torpedo tubes in the bow and stern.
Twelve boats were ordered, but only two were completed, by Tosi:
The remaining 10 hulls were scuttled incomplete and scrapped after the war.
The sail of submarine R12 is now exhibited as a monument on the seafront of Gaeta.