The vessel weighs 600 tonnes and is armed with torpedoes, naval mines and cruise missiles that can be launched from a submerged position, the government’s English-language Press TV said.
Iran has developed a large domestic arms industry in the face of international pressure and embargoes that have barred it from importing many weapons. The Fateh is its first domestically produced cruise-missile submarine.
The Iranian navy already possesses at least three Russian-built Kilo class attack submarines and domestically-produced midget submarines.
Last year it launched a domestically built destroyer which state media said has radar-evading stealth properties.
Donald Trump, the president of the United States, pulled out of a 2015 nuclear agreement and reimposed sanctions on Tehran in May 2018, saying the deal did not sufficiently curb Iran’s development of ballistic missiles.