Largest U-boat victims
HMS Barham sinking after U-331's torpedo hits
Since the tonnage between merchants and warships cannot be directly compared this list is shown in parts.
Merchant ships
Allied merchant ships of 15,000 GRT and more sunk by German U-boats during the Second World War. This list includes auxiliary warships such as armed merchant cruisers (AMC's).
| Date | Name of vessel and U-boat responsible |
| 28 Oct 1940 | Empress of Britain (42.348 GRT) a steam passenger ship sunk by U-32 (Jenisch) |
| 21 Dec 1942 | Strathallan (23.722 GRT) a troop transport sunk by U-562 (Hamm) |
| 10 Oct 1942 | Orcades (23.456 GRT) a troop transport sunk by U-172 (Emmermann) |
| 7 Mar 1941 | Terje Viken (20.638 GRT) a whale factory ship sunk by U-99 (Kretschmer) |
| 6 Jun 1940 | HMS Carinthia (20.277 GRT) an Armed Merchant Cruiser sunk by U-46 (Endrass) |
| 10 Oct 1942 | Duchess of Atholl (20.119 GRT) a steam passenger ship sunk by U-178 (Ibbeken) |
| 14 Nov 1942 | Warwick Castle (20.107 GRT) a troop transport sunk by U-413 (Poel) |
| 12 Sep 1942 | Laconia (19.695 GRT) a troop transport sunk by U-156 (Hartenstein) |
| 11 Nov 1942 | Viceroy of India (19.627 GRT) a troop transport sunk by U-407 (Brüller) |
| 3 Nov 1940 | HMS Laurentic (F 51) (18.724 GRT) an Armed Merchant Cruiser sunk by U-99 (Kretschmer) |
| 7 Dec 1942 | Ceramic (18.713 GRT) a steam passenger ship sunk by U-515 (Henke) |
| 13 Jun 1940 | HMS Scotstoun (17.046 GRT) an Armed Merchant Cruiser sunk by U-25 (Beduhn) |
| 17 Mar 1944 | Dempo (17.024 GRT) a troop transport sunk by U-371 (Mehl) |
| 29 Oct 1942 | Kosmos II (16.966 GRT) a whale factory ship sunk by U-624 (Soden-Fraunhofen) |
| 10 Aug 1940 | HMS Transylvania (F 56) (16.923 GRT) an Armed Merchant Cruiser sunk by U-56 (Harms) |
| 13 Apr 1941 | HMS Rajputana (F 35) (16.644 GRT) an Armed Merchant Cruiser sunk by U-108 (Scholtz) |
| 2 Dec 1940 | HMS Forfar (F 30) (16.402 GRT) an Armed Merchant Cruiser sunk by U-99 (Kretschmer) |
| 8 Sep 1944 | Empire Heritage (15.702 GRT) a steam tanker sunk by U-482 (Matuschka) |
| 2 Jul 1940 | Arandora Star (15.501 GRT) a steam passenger ship sunk by U-47 (Prien) |
| 3 Feb 1942 | Amerikaland (15.355 GRT) a motor merchant sunk by U-106 (Rasch) |
| 27 Aug 1940 | HMS Dunvegan Castle (15.007 GRT) an Armed Merchant Cruiser sunk by U-46 (Endrass) |
21 ships larger than 15,000 GRT sunk (409.996 total GRT) | |
Warships
Warships of 4,000 tons and more sunk by German U-boats during the Second World War.
| Date | Name of vessel and U-boat responsible |
| 25 Nov 1941 | HMS Barham (04) (31.100 tons) a battleship sunk by U-331 (Tiesenhausen) |
| 14 Oct 1939 | HMS Royal Oak (08) (29.150 tons) a battleship sunk by U-47 (Prien) |
| 13 Nov 1941 | HMS Ark Royal (91) (22.600 tons) an aircraft carrier sunk by U-81 (Guggenberger) |
| 11 Aug 1942 | HMS Eagle (94) (22.600 tons) an aircraft carrier sunk by U-73 (Rosenbaum) |
| 17 Sep 1939 | HMS Courageous (50) (22.500 tons) an aircraft carrier sunk by U-29 (Schuhart) |
| 15 Nov 1942 | HMS Avenger (D 14) (13.785 tons) a escort carrier sunk by U-155 (Piening) |
| 21 Dec 1941 | HMS Audacity (D 10) (11.000 tons) a escort carrier sunk by U-751 (Bigalk) |
| 29 May 1944 | USS Block Island (CVE 21) (9.393 tons) a escort carrier sunk by U-549 (Krankenhagen) |
| 11 Mar 1942 | HMS Naiad (93) (5.450 tons) a light cruiser sunk by U-565 (Jebsen) |
| 16 Jun 1942 | HMS Hermione (74) (5.450 tons) a Light cruiser sunk by U-205 (Reschke) |
| 18 Feb 1944 | HMS Penelope (97) (5.270 tons) a light cruiser sunk by U-410 (Fenski) |
| 15 Dec 1941 | HMS Galatea (71) (5.220 tons) a light cruiser sunk by U-557 (Paulshen) |
| 24 Nov 1941 | HMS Dunedin (D 93) (4.850 tons) a light cruiser sunk by U-124 (Mohr) |
13 warships larger than 4,000 tons sunk (188.368 total tons). | |