The HS Nirefs is the second Greek submarine with this name.

The first (Y-4) was of French design and construction [Loire – Simonot type, improved version of the HS Katsonis (Y-1) / HS Papanikolis (Y-2) submarines)], one of four of the similar type that were ordered to France by the Greek government in 1927. She was built at the “Chantiers de la Loire” shipyards in St Nazaire, with Lieutenant Commander S. Tsirimokos as first Captain. She was received in Brest on April 4, 1930 – along with HS TRITON (Y-5) – and sailed to the Salamis Naval Base on April 26, 1930.

During the Second World War, she operated in the Adriatic and Aegean Sea, as well as from the strait of OTRANTO to Kastellorizo, carrying out a total of twenty war patrols, transporting commandos from occupied Greece and sinking, among others, the Italian gunboat FLUME (1500 tons) in the area of the island Rhodes, an Italian merchant ship of 7000 tons etc. She was decommissioned due to her age on May 3, 1947, and sold for scrapping in 1952.

The HS Nirefs (S-111) is a German type 209/1100 (INGNIEUR KONTOR LUBECK – IKL), the second of the four submarines of the “GLAFKOS” class ordered and built at HDW shipyards in Kiel, Germany. She was launched on 9 June 1971 and received by the Hellenic Navy on February 10, 1972 with Lieutenant Commander G. Sideris HN, when she joined the Fleet Headquarters Force.

On March 6, 1998, she started the NEPTUNE-I, Mid-Life Modernization Program, for the upgrade of naval systems. The work was completed on January 27, 2000.

Since then, she continues to support the operations of the Fleet Headquarters, being the oldest operational submarine T.209/1100 in the world.