The Nazario Sauro class are diesel-electric submarines operated by the Italian Navy.

Italy developed the Sauro-class submarines in the 1970s to counter the underwater threat of the Soviet Union.

In 1983 and 1988 two additional pairs of boats were ordered to the Improved Sauro class design.

The plan called for the US to purchase four submarines when decommissioned, then refurbish them in the US and sell them to Taiwan.

Once refurbished, the Italian submarines were expected to be operational for another 15 years, and the deal included an extension program.