| | Commander | Warship commands |
 | | Lt.Cdr. | I'Anson, Brian Mortimer Duncan, RN | HMS Leamington (G 19), HMS Meynell (L 82), HMS Rocket (H 92) |
 | | T/Cdr. | Icenhower, Joseph Bryan, USN | USS Jallao (368) |
| | T/Lt. | Ife, Herbert John, RNVR | HMS Rainstorm (FY 1920) |
| | T/Capt. | Ignatius, William Russell, USN | USS S-22 (127) |
| | T/Capt. | Ihrig, Russell Million, USN | USS Cimarron (AO 22), USS Canberra (CA 70) |
| | | Ikenberry, Jr., Henry C., USNR | USS PCE-873 (PCE-873) |
| | T/Lt. | Ilett, Norman Leonard, DSC, RNVR | HMS MTB 84 (MTB 84), HMS MTB 378 (MTB 378), HMS MTB 420 (MTB 420) |
| | | Illingworth, R, RNVR | HMS MMS 1049 (FY 1049) |
| | | Illingworth, C J, RNR | HMS Alice (FY 003) |
| | T/Lt. | Illingworth, Arthur, RNVR | HMS Strephon (FY 1829) |
| | T/Cdr. | Ilsemann, Frederick Joseph, USN | USS Monongahela (AO 42) |
|  | A/Lt.Cdr. | Impey, Michael Elijah, DSO, DSC, RN | HMS Spey (K 246), HMS Taff (K 637) |
| | T/Lt. | Inderwick, Charles Cyril, RNVR | HMS M 2 (M 34) |
| | | Ingebrand, Charles Daniel, USNR | USS Childs (AVD 1) |
| | T/Vice-Admiral | Ingersoll, Royal Eason, USN | |
| | T/R.Adm. | Ingersoll, Stuart Howe, USN | USS Monterey (CVL 26) |
| | Capt. (Retd.) | Ingham, James Geoffrey Penrose, DSO, RN | HMS Alcantara (F 88) |
| | Lt.Cdr. | Ingham, Theodore, USN | USS Cinchona (AN 12), USS Hoptree (AN 62) |
| | Lt.Cdr. | Ingle, Jr., John Pierce, USNR | USS Manlove (DE 36), USS Doyle C. Barnes (DE 353) |
| | T/Cdr. | Ingling, Francis Walford, USN | USS Abbot (ii) (DD 629) |
| | T/A/Lt.Cdr. | Inglis, H A, RNR | HMS Linnet (M 69) |
| | T/A/Ch.Skr. | Inglis, James, RNR | HMS Cerisio (FY 524), HMS General Birdwood (FY 724) |
| | Lt.Cdr. | Inglis, Alexander Douglas Colin, RN | HMAS Warrego (L 73 / U 73), HMS Black Swan (L 57 / U 57) |
| | T/R.Adm. | Inglis, Thomas Browning, USN | USS Birmingham (CL 62) |
| | | Ingraham, H W, USNR | USS PCS-1446 (PCS-1446) |
| | | Ingram, M.A., RNVR | HMS ML 153 (ML 153) |
| | T/A/Lt.Cdr. | Ingram, Ralph Thomas, RCNR | HMCS Gaspe (J 94), HMCS Gaspe (J 94), HMCS Melville (J 263) |
| | A/Capt. | Ingram, David Caldicott, DSC, OBE, RN | HMS Phoenix (N 96), HMS Clyde (N 12), HMS Cyclops (F 31) |
| | Cdr. | Ingram, John Charles Anthony, DSC, RN | HMS Cottesmore (L 78), HMS Oribi (G 66) |
| | Capt. | Ingram, Jonas Howard, USN | USS Tennessee (BB 43) |
| | A/Capt. | Inigo-Jones, Henry Richmond, RIN | HMIS Investigator (J 81), HMIS Clive (L 79 / U 79) |
| | | Inman, W, RNR | HMS Ben Idris (FY 1766), HMS Lord Darling (FY 1774) |
| | T/Lt. | Inman, Cecil Postlethwaite, RNVR | HMS Lord Melchett (FY 672), HMS MMS 187 (J 687) |
| | | Inman, Edward Herman, USNR | USS Montgomery (DM 17) |
| | Skr. | Innes, Green, RNR | HMS Southern Star (FY 329) |
| | T/Cdr. | Innis, Walter Deane, USN | USS Bering Strait (AVP 34) |
| | Capt. | Ionides, Hugh Meynell Cyril, RN | HMS Titania (F 32), HMS Maidstone (F 44), HMS Titania (F 32), HMS Forth (F 04), HMS Roberts (F 40), HMS Adamant (F 64) |
| | T/Capt. | Irvin, William Davis, USN | USS S-29 (134), USS Nautilus (168) |
| | Cdr. (emergency) | Irvine, Charles Duncan Alexander, DSC, RN | HMS Grecian (J 352) |
| | T/Cdr. | Irvine, Donald Greer, USN | USS Piranha (389) |
| | Lcmdr | Irvine, James McCabe, USNR | USS Otter (DE 210) |
| | A/Cdr. (retired) | Irvine, George Walter Alexander Thomas, DSC, RNR | HMS Fraserburgh (J 124), HMS Whitehaven (J 121), HMS Romney (J 77), HMS Dodman Point (F 19) |
| | | Irvine, Robert Klink, USN | USS Cushing (ii) (DD 797) |
| | Cdr. | Irving, Edmund George, OBE, RN | HMS Franklin (J 84) |
| | T/Lt. | Irving, Charles Edgar, RNVR | HMS Leicester City (FY 223), HMS Leicester City (FY 223) |
| | | Irwin, Ungar, USNR | USS Chandler (DMS 9) |
| | | Irwin, Henry J., USNR | USS PCE(R)-852 (PCE(R)-852) |
| | Lt.Cdr. | Isaacs, Vernon Aaron, USNR | USS Edsall (ii) (DE 129), USS Reuben James (ii) (DE 153) |
| + | T/Capt. | Isbell, Arnold Jay, USN | USS Card (CVE 11) |
| | | Iseli, R L, USNR | USS PC-492 (PC-492), USS PC-809 (PC-809) |
| | Lt. | Iselin, Lewis, USNR | USS PC-563 (PC-563), USS Atherton (DE 169) |
| | | Isenberg, F. M. R., USNR | USS YMS-11 (YMS-11), USS YMS-11 (YMS-11) |
| | T/Capt. | Isgrig, Clayton Shadek, USN | USS Preston (i) (DD 379), USS Brazos (AO 4), USS Orion (AS 18) |
| | Lt,Cdr. | Islemann, Frederick Joseph, USN | USS Vireo (AM 52) |
| | T/A/Lt.Cdr. | Israel, Neil Frederick, DSC, RNR | HMS Dianthus (K 95), HMS Keats (K 482) |
| | Cdr. | Ivaldi, Joseph Albert, USNR | USS Elokomin (AO 55) |
| | T/Cdr. | Iverson, Clifton, USN | USS Dunlap (DD 384), USS Hawkins (DD 873) |
| | T/Capt. | Ives, Norman Seaton, USN | USS Narwhal (167) |
| | A/Lt.Cdr. | Ives, William Arthur, RNR | HMS La Malouine (K 46) |
| | T/Lt. | Ivison, Norman John, DSC, RNVR | HMS Cape Mariato (4.172) |
| | T/Lt. | Iwanski, Jan, RNR | HMS LST 394 (LST 394) |
| | | Izod, J, RNVR | HMS MMS 71 (J 571) |
| A (453), B (1545), C (1253), D (754), E (315), F (543), G (687), H (1291), I (62), J (403), K (425), L (651), M (1401), N (265), O (177), P (764), Q (21), R (741), S (1410), T (563), U (24), V (145), W (1045), Y (60), Z (20), Ø (1) |
