She was built as a Type 207 submarine by Rheinstahl-Nordseewerke of Emden, Germany in 1965 for the Royal Norwegian Navy and served for 25 years as HNoMS Uthaug before being purchased by Denmark in 1990, and renamed after the seal.

On 4 December 1990, Sælen sank in the Kattegat off Hesselø while being towed from Copenhagen to Aarhus.

To speed her return to her homeport of Frederikshavn after 385 days of deployment in the Mediterranean Sea and the Persian Gulf, she was transported on board the heavy-lift ship Grietje.

After her return from the Persian Gulf, Sælen was decommissioned and handed over to the Royal Danish Naval Museum.

Sælen is now on the hard at the old navy headquarters at Holmen in central Copenhagen where she is open to visitors.