17 Nov, 1944
At 0355 hours 40 nautical miles north-west of the Stilo lighthouse, L-21 fires three torpedoes at what is identified as a small merchant of about 500 tons. All torpedoes missed their target.

23 Nov, 1944
L-21 lays a minefield off the Stolpebank.

That same day the German merchant Eichberg (1923 GRT) hits one of these mines and sank in position 54º51'N, 17º59'E. (see map)

24 Nov, 1944
The German merchant Elie (1837 GRT) hits a mine and sinks in position 54º51N, 17º59'E. The mine was laid the previous day by the Russian submarine L-21.

Also on this day, L-21 torpedoes and sinks the small Swedish passenger ship Hansa (563 GRT) 18 nautical miles north-west of Halskuk in position 58º02'N, 18º10'E. (see map)

22 Dec, 1944
The German merchant Eberhard (749 GRT) hits a mine and sinks in position 54º51'N, 17º59'E. The mine was possibly laid on 23 November 1944 by the Russian submarine L-21.

Also on this day, L-21 engages a so far unidentified enemy merchant with gunfire 16 nautical mines north of Brüsterort. (see map)

8 Mar, 1945
L-21 lays a minefield off Hela.

14 Mar, 1945
The German torpedo boats T-3 and T-5 (both 839 tons) are mined and sunk off Hela in position 54º39'N, 18º47'E. The mines were laid by the Soviet submarine L-21 on 8 March 1945. (see map)

16 Mar, 1945
The German submarine U-367 (769 tons) was sunk in the Baltic Sea near Hela, in position 54º25'N, 18º50'E, after hitting a mine laid by the Soviet submarine L-21 laid on 13 March 1945. (see map)

18 Mar, 1945
While on patrol east of the Stolpebank, at 2305 hours L-21 fires three torpedoes at a so far unidetified merchant in a German convoy. All torpedoes missed their target.

At 2332 hours L-21 again fires three torpedoes at a so far unidetified merchant in another German convoy. Once again all torpedoes missed their target.

23 Mar, 1945
L-21 torpedoes and sinks the German auxiliary patrol vessel V 2022/E Colzmann (581 GRT) off Kolberg in position 55º24'N, 17º00'E. (see map)

24 Mar, 1945
L-21 torpedoes and sinks the German tug Erni (105 GRT) off Kolberg in position 55º10'N, 17º36'E. (see map)

10 Apr, 1945
The German destroyer Z-43 (2519 tons) is mined and damaged off Hela in position 54º36'N, 18º52'E. The mines were laid by the Soviet submarine L-21 on 8 March 1945. (see map)