These submarines have a displacement of 1,660 tons when surfaced, a speed of 22 knots (41 km/h; 25 mph), and a complement of 40 including eight officers.

The refit was carried out by MDL at Mumbai with technical cooperation from ThyssenKrupp Marine Systems.

[9][10] The refit was planned to be completed by 2021 with a similar upgrade for another vessel of Shishumar-class submarine to follow.

[11] Similarly, a second mid-life upgrade contract was awarded to the Mazagon Dock for refit and life certification of the 2nd submarine Shankush on 30 June 2023.

[12] Total 3 ships out of 4 will undergo mid-life refit and certification, this will extend the life of the submarine by 10–15 years.