|Laid Down:||31 May 1965|
|Launched:||3 October 1965|
|Purchased:||11 July 1990|
|Commissioned:||10 October 1990|
|Displacement:||370 tons surfaced, 435 tons submerged|
|Propulsion:||two MTU 1100 hp diesel engines, one 1700 hp electric motor|
|Speed:||10 knots surfaced, 17 knots submerged|
|Complement:||24 officers and men|
|Armament:||eight 533mm (21-inch) torpedo tubes, eight torpedoes|
On 4 December 1990, Sælen sank while being towed from Copenhagen to Aarhus. On 17 December, she was raised by the German floating crane Roland and taken to Aarhus for repair. On 10 August 1993, diving approval was issued and the boat was recommissioned.
Sælen served in the 2003 invasion of Iraq from May 2002 until June 2003. 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.
"Sælen" means "seal" in English.