Italian Navy submarine Scirè (S527) collided with a merchant vessel in the evening of May 10, the navy said in a statement.
According to the navy, no one was injured and the merchant vessel was able to proceed under its own propulsion.
The Type 212 submarine was returning from exercises, transiting the Gulf of Squillace in the Ionian Sea when the incident happened.
The submarine has continued her return to the homeport while the incident is under investigation, the navy said.
ITS Scirè (S527) is the second of four Italian Navy Todaro-class submarines. She was built by Italian shipbuilder Fincantieri and commissioned into service in 2007.