Marketed by the French government for the export market, the Daphné design went on to serve in South Africa while there were subclasses based on the Daphné design that were commissioned in the navies of Pakistan, Portugal, and Spain.

Their design emphasized maneuverability, low noise production and ease of maintenance.

[1] Each vessel of the class was fitted with two SEMT-Pielstick diesel engines, with two 450-kilowatt diesel generator sets, and two electric motors turning two shafts creating 750 kilowatts (1,000 shp) sustained with the ability to create 970 kW (1,300 shp) for short periods.

[1][2] The submarines also mounted DSUV 2 passive sonar and DUUX 2 acoustic telemeter.

The boats were planned for disposal in the 1980s, however, the slow delivery of their nuclear submarine replacements led to their careers being extended.

This left the United Kingdom and France as the only countries with the extra shipbuilding capability to build ships for export.

[7] Smaller navies opted for the Daphnés or in the case of Spain, were rejected by the United Kingdom.

[9] The Hangor class used the 12 PA4-135 type diesel engines and had a complement of 5 officers and 45 sailors.

[10] Their interior differed from the French model in order to meet Pakistan's requirements.

PNS Hangor sank the Indian frigate INS Khukri during the 1971 Indo-Pakistani war.

The submarines were of prefabricated design with component sections being constructed between 1 October 1964 and 6 September 1965.

[21] As part of Spain's attempt to build up their shipbuilding industry in the post-World War II era, they sought to learn techniques from various nations by acquiring ships from them, such as American destroyers and submarines.