The German merchant Bessheim (1774 GRT) is mined and sunk off Hammerfest in position 70º39'N, 23º38'E. The mine was laid K-21 on 11 November 1941. (see map)

9 Nov, 1941
While on patrol off Hammerfest, northern Norway K-21 fires two torpedoes at what is identified as a merchant. The torpedoes however miss their target.

12 Nov, 1941
At 1420 hours K-21 attacks the German auxiliary patrol vessel V 6109/Nordwind with three torpedoes in position 70º43'N, 24º04'E. The torpedoes all miss their target.

During the same attack at 1429 hours K-21 fires two torpedoes at what is identified as a merchant of approx. 5000 GRT. These torpedoes also miss their target. (see map)

13 Jan, 1942
K-21 fires two torpedoes at the German merchant Fechenheim (8116 GRT) off northern Norway in position 70º50'N, 23º50'E. The torpedoes however miss their target. (see map)

31 Mar, 1942
K-21 attacks a German convoy of the Syltefjord, northern Norway. The torpedoes fires miss the German merchant Admiral Karl Hering (1436 GRT).

5 Jul, 1942
K-21 fires four stern torpedoes against the German battleship Tirpitz off Ingøy Island, Norway in position 71º22'N, 24º34'E. The torpedoes however miss their target. (see map)

9 Jul, 1942
The German auxiliary submarine chaser UJ 1110 (527 GRT) is mined and sunk off the Mageroysund in position 70º39'N, 23º38'E. The mine was laid by either the Russian submarine K-3 on 23 November 1941 or the Russian submarine K-21 on 11 November 1941. (see map)

16 Aug, 1942
K-21 lays a minefield in Lopphavet.

19 Aug, 1942
K-21 fires four torpedoes at the German merchant Sèvre (5089 GRT, former French) and two small escorts in Lopphavet in position 70º27'N, 21º39'E. All torpedoes however miss their target. (see map)

23 Oct, 1942
K-21 was awarded the Red Banner Award.

12 Feb, 1943
K-21 sinks four small Norwegian motor boats with gunfire in Lopphavet.

18 Feb, 1943
K-21 lays a minefield in the Lyngenfjord.

9 Apr, 1943
K-21 fires 6 torpedoes against the German minelayer Brummer in the Batsfjord in position 70º34'N, 21º38'E. All torpedoes missed their target. (see map)

12 Apr, 1943
K-21 sinks four Norwegian fishing vessels with gunfire in Lopphavet off Svendsgrunn.

22 Apr, 1943
The German merchant Duna (1926 GRT) is mined and sunk in the Lyngenfjord. The mine was laid by K-21 on 18 February 1943.