Warships of the Imperial Japanese Navy, First Class Submarines in the Second World War

Japanese submarines of the Second World War

(Official USN Photo, located at the US National Archives, CVE-29 Photo, 80-G-353701)

Former IJN units at Kure harbour, Honshu, Japan, on 12 October 1945.

Imperial Japanese Navy (IJN) submarines formed by far the most varied fleet of submarines of the Second World War, including manned torpedoes (Kaiten), midget submarines (Kō-hyōteki, Kairyū), medium-range submarines, purpose-built supply submarines (many used by the Imperial Japanese Army, see Type 3), fleet submarines (many of which carried an aircraft), submarines with the highest submerged speeds of the conflict (Sentaka I-201-class), and submarines able to carry multiple bombers (Second World War's largest submarine, the Sentoku I-400-class). They were also equipped with the advanced oxygen-fuelled Type 95 Torpedo (which is sometimes confused with the famed Type 93 Long Lance torpedo).

Overall, despite their advanced technical innovation, Japanese submarines were built in relatively small numbers and had less effect on the war than those of the other major navies. The IJN pursued the doctrine of guerre d'escadre (fleet vs fleet warfare), and consequently submarines were often used in offensive roles against warships. Warships were more difficult to attack and sink than merchant ships, however, because naval vessels were faster, more maneuverable, and better defended.

The IJN submarine arm did have a number of notable successes against American warships, however. During the Battle of Midway, I-168 administered the final coup de grace that sank the fleet carrier USS Yorktown, as well as sinking the destroyer USS Hammann. A few months later, on 15 Sep 1942,with a single salvo of torpedoes, Japanese submarine I-19 sank the fleet carrier USS Wasp and damaged both the battleship USS North Carolina and the destroyer USS O'Brien. On 13 Nov 1942, the submarine I-26 torpedoed and sank the anti-aircraft cruiser USS Juneau, and a year later on 23 Nov 1943, the submarine I-175 torpedoed and sank the escort carrier USS Liscome Bay, both with heavy loss of life. The I-176 had the distinction of both severely damaging the heavy cruiser USS Chester, knocking her out of the war for a year, on 20 Oct 1942, and of also sinking USS Corvina (the only American submarine to be sunk by a Japanese submarine in the entire war) on 16 Nov 1943.

Twice in the first year of the war, Japanese submarines torpedoed the aircraft carrier USS Saratoga, and, while not sinking her, put her in the repair yard at a time when the US Navy could ill afford to do without her.USS Saratoga was torpedoed by submarine I-6 on 11 Jan 1942, putting her out of action and unavailable to participate in the desperate carrier battles and raids of the next five months, and then hit again three months after her return on 1 Sep 1942, by I-26, which put her out of action for another eleven weeks in the middle of the intensely engaged land-air-sea battles of the Guadalcanal Campaign.

A plane launched from one of the innovative aircraft-carrying submarines, I-25, conducted what remains the only ever aerial bombing attack on the continental United States, when Warrant Flying Officer Nobuo Fujita piloting a Yokosuka E14Y scouting plane dropped four 168-pound bombs in an attempt to start forest fires outside the town of Brookings, Oregon, on 9 Sep 1942. Earlier in the year, in Feb 1942, the submarine I-17 fired a number of shells from her deck gun at the Elwood Oil Fields near Santa Barbara, California. None of the shells caused any serious damage.

However, as fuel oil diminished and air superiority was lost, Imperial submarines were no longer able to continue with such successes. Once the United States was able to increase its production of destroyers and destroyer escorts,as well as bringing over highly effective anti-submarine techniques learned during the Battle of the Atlantic, they continually took more and more of a toll on Imperial Japanese submarines, which also tended to be not as deeply diving as their Kriegsmarine counterparts.

Accordingly, the Japanese submarine arm had few notable successes against Allied warships during the final two years of the war. One victory was the I-41 knocking the anti-aircraft cruiser USS Reno out for the rest of the warwith a torpedo hit on 3 Nov 1944 (this was the first time in almost two years that a Japanese submarine had successfully attacked an Allied ship operating with a fast carrier task force. A more famous incident was the I-58 torpedoing and sinking heavy cruiser USS Indianapolis, with heavy loss of life. The sinking occurred on 30 July 1945, just two weeks before the Japanese surrender, at a time when few in the United States Navy expected continued Japanese submarine attacks.

The Imperial Japanese Navy's doctrine of fleet warfare (guerre d'escadre) resulted in its submarines seldom posing a threat to allied merchant convoys and shipping lanes to the degree that the Kriegsmarine's U-boats did as they pursued commerce raiding against Allied and neutral merchant ships. During the war, IJN submarines did sink about 1 million tons (GRT) of merchant shipping (184 ships) in the Pacific; by contrast U.S. Navy submarines sank 5.2 million tons (1,314 ships) in the same period, while U-boats of Nazi Germany's Kriegsmarine, the IJN's Axis partner, sank 14.3 million tons (2,840 ships) in the Atlantic and other oceans. During the last two years of the War in the Pacific, many IJN submarines were also occupied serving to transport supplies to isolated island garrisons, ones that had been deliberately by-passed by the Americans and the Australians and which could not be reached by surface transports because of blockades by Allied warplanes and naval vessels.

Early models of IJN submarines were relatively less maneuverable under water, could not dive very deeply, and lacked radar. (Later in the war units that were fitted with radar were in some instances sunk due to the ability of American radar sets to detect their emissions. For example, USS Batfish sank three such IJN submarines near Japan in just four days). After the end of the conflict, several of Japan's most innovative and advanced submarines were sent to Hawaii for inspection in "Operation Road's End" (I-400, I-401,I-201, and I-203) before being scuttled by the U.S. Navy in 1946, when the Soviet Union demanded access to the IJN submarines. (Wikipedia)

Japanese Submarines by Class

First-class submarines

This class includes the largest of Japanese submarines, characterized by great size and range.

The Kaidai I type (海大I型, Navy large type I) (I-51-class) submarine was the prototype for the types (KD2-KD7) that followed and was based on the German cruiser submarine U-139 and the British L-class submarine.

I-51. The Kaidai I type (海大I型, Navy large type I) (I-51-class) submarine was the prototype for the types (KD2-KD7) that followed and was based on the German cruiser submarine U-139 and the British L-class submarine. I-51 was scrapped in 1941.

The Kaidai II type (海大II型, Navy large type II) (I-152-class) submarine was based on U-139 and the British K-class submarine.

I-52/152. The Kaidai II type (海大II型, Navy large type II) (I-152-class) submarine was based on U-139 and the British K-class submarine. I-52/I-152 – scrapped 1946–1948.

‍Kaidai IIIa, I-153-class

Submarines I-53/I-153, I-54/I-154, I/55/I-155, I-58/1-158.

1,575 tonnes. The official designation of the submarine was Kaidai-type submarine. The Kaidai IIIa type (海大IIIa型, Navy large type IIIa) (I-153-class) submarines were similar to the Type KD1 and KD2 but with strengthened hulls. In 1945, I-155 and I-158 were modified as Kaiten suicide torpedo carriers, each armed with two Kaitens.

I-53/I-153 – sank Ben 2 on 20 Feb in the Indian Ocean, SS Moesi in the Bali Strait on 27 Feb 1942 and SS City of Manchester off Java on 28 Feb 1942. I-153 was sunk as a target by HMAS Quiberon and HMIS Sutlej in the Seto Island Sea on 8 May 1946 as part of Operation Bottom, although some sources claim she was scrapped in 1948 rather than sunk.

(IJN Photo)

IJN submarineI-54/ I-154. She conducted three war patrols during the war, supporting Japanese forces during the invasion of Malaya in December 1941 and the Dutch East Indies campaign in early 1942, then was assigned to training duties until she was decommissioned in 1944. She was scuttled by gunfire from HMAS Quiberon and HMIS Sutlej in the Seto Island Sea on 8 May 1946 as part of Operation Bottom.

I-55/I-155 – sank SS Van Cloon off Java on 7 Feb 1942 and RMS Derrymore in the Java Sea on 13 Feb 1942. I-155 herself surrendered 2 Sep 1945 and was scuttled by gunfire from HMAS Quiberon and HMIS Sutlej in the Seto Island Sea on 8 May 1946 as part of Operation Bottom.

I-58/I-158 – sank SS Langkoeas in the Java Sea on 3 Jan 1942, SS Camphuys off Bawean Island on 9 Jan 1942, SS Pijnacker Hordijk between Tjilatjap and Padang on 22 Feb 1942 and SS Boeroe south of the Sunda Strait on 25 Feb 1942. I-158 herself surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 as part of Operation Road's End.

The Kaidai IIIb type (海大IIIb型, Navy large type IIIb) (I-156-class) submarines were similar to the Type KD3a but were 16 inches longer and had a different bow shape.

Submarines I-56/I-156, I-57/I-157, I-59/I-159, I-60, I-61, I-63.

I-56/I-156 – sank five merchant ships. I-156 surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 by USS Nereus as part of Operation Road's End.

(National Archives Photo, 80-G-260245)

Operation "Road's End", Japanese submarines I-156 and Ha-203 are prepared for scuttling, off Sasebo, Japan, 1 April 1946. U.S. Navy ships and other Japanese ships are in the background.

I-57/I-157 – sank SS Djirak on 7 Jan 1942. I-157 surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 by USS Nereus as part of Operation Road's End.

I-59/I-159 – sank SS Rooseboom off Sumatra on 1 Mar 1942. I-159 surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 by USS Nereus as part of Operation Road's End.

I-60 – Accidentally rammed I-63 off Mizunoko Light on 2 Feb 1939. I-60 herself was sunk off Krakatoa Island on 17 Jan 1942 by HMS Jupiter.

I-63 – Accidentally rammed by I-60 off Mizunoko Light on 2 Feb 1939. Refloated Jan 1940 and then scrapped.

The Kaidai IV type (海大IV型, Navy large type IV) (I-61/I-162-class) submarines were slightly smaller and had four torpedo tubes, but were otherwise similar to the Type KD3.

Submarines I-61, I-62/I-162, I-164.

I-61. I-61 Sunk in collision with gunboat Kiso Maru in Koshiki Channel on 2 Oct 1941. Refloated in early 1942 and sold for scrap.

I-62/I-162 – Sank Mikoyan on 3 Oct 1942, Manon on 7 Oc 1942 and Fort McCloud on 22 Feb 1944. The I-162 surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 by USS Nereus as part of Operation Road's End.

I-164. I-64/I-164 – Sunk off Cape Ashizuri on 17 May 1942 by USS Triton.

The Kaidai V type (海大V型, Navy large type V) (I-165-class) submarines were similar to the Type KD4 but had an improved operating depth.

Submarines , I-65/I-165, I-66/I-166, I-67.

I-165. I-65/I-165 – Depth-charged off Saipan on 27 June 1945 by a US Navy patrol bomber of VPB-142.

I-66/I-166 – Sunk off One Fathom Bank on 17 July 1944 by HMS Telemachus.

I-67 – Sank in diving accident off Minamitorishima on 29 Aug 1940.

Kaidai VIa type (海大VIa型, Navy large type VIa) (I-168-class) submarines were similar to the KD5 but with a higher speed.

Submarines I-68/I-168, I-69/I-169, I-70, I-71/I-171, I-72/I-172, I-73.

I-68/I-168 – Sunk in the Steffen Strait on 27 July 1943 by USS Scamp.

I-69/I-169 – Sank in diving accident in Truk Lagoon on 4 Apr 1944.

I-70 – Sunk by a Douglas SBD Dauntless aircraft from VS-6 (USS Enterprise) on 10 Dec 1941. This was the first enemy combatant ship sunk by U.S. forces.

I-71/I-171 – Depth-charged off Buka Island on 1 Feb 1944 by USS Guest and USS Hudson.

I-72/I-172 – Missing after 28 Oct 1942. Possibly depth-charged off San Cristóbal by USS McCalla on 3 Nov 1942.
‍

I-173. I-73 – Sunk by USS Gudgeon on 27 Jan 1942. I-73 was the first warship sunk by a US Navy submarine.

Kaidai VIb type (海大VIb型, Navy large type VIb) (I-174-class) submarines were similar to the KD6a but were one foot longer and 25 tons heavier.

Submarines I-174, I-175.‍

I-174 – sunk off Truk on 12 Apr 1944 by aircraft from VB-108.

I-175 – sunk off Wotje Atoll on 17 Feb 1944 by USS Nicholas.

Kaidai VII type (海大VII型, Navy large type VII) or Shin Kaidai type (新海大型, New navy large type) (I-176-class) submarines were similar to the KD6 but with the torpedo tubes moved forward and a slightly improved operating depth.

Submarines , I-76/I-176, I-77/I-177, I-78/I-178, I-79/I-179, I-80/I-180, I-81/I-181, I-82/I-182, I-83/I-183, I-84/I-184, I-85/I-185.

I-76/I-176 – sank USS Corvina patrolling off Truk on 16 Nov 1943, the only known Japanese submarine success against a US submarine – USS Snook was a probable second victim by Japanese submarines. I-176 was lost a year later off Buka Island on 16 May 1944, depth-charged by USS Franks, USS Haggard, and USS Johnston.

I-177 – Sank AHS Centaur off Australia on 14 May 1943. The I-177 was sunk by USS Samuel S. Miles on 3 Oct 1944.

I-78/I-178 – Missing after 17 June 1943. Possibly sunk 25 Aug 1943 near the Solomon Islands by USS Patterson.

I-79/I-179 – Sank during sea trials in the Seto Island Sea on 14 July 1943. Salvaged 1956-1957 and then scrapped.

I-80/I-180 – Sunk off Chirikof Island on 27 Apr 1944 by USS Gilmore.

I-81/I-181 – Ran aground and sunk in Kelanoa Harbour on 16 Jan 1944.

I-82/I-182 – Sunk off the New Hebrides on 1 Sep 1943 by USS Wadsworth.

I-83/I-183 – Sunk near the Bondo Strait on 29 April 1944 by USS Pogy.

I-84/I-184 – Sunk near Saipan on 19 June 1944 by a torpedo bomber from USS Suwanee.

I-85/I-185 – Sunk near Saipan on 22 June 1944 by USS Newcomb and USS Chandler.

Type J1 (I-1, I-2, I-3, I-4)

The Junsen I type (巡潜I型, Cruiser submarine Type I) (I-1-class) submarines were based on the Kaidai II (Type KD2) and German submarine U-142.

Submarine I-1, I-2, I-3, I-4, I-5, I-6, I-7, I-8.

‍1,970 tonnes. The official designation of the submarine was Junsen-type submarine.

I-1 – sank SS Siantar off Western Australia on 3 Mar 1942. I-1 was attacked by HMNZS Kiwi and ran aground on Fish Reef 29 Jan 1943; valuable codes and code books from the wreck were salvaged by Allied forces.

I-2 – sank HMS Nam Yong off Christmas Island on 28 Feb 1942, and SS Parigi in the Indian Ocean on 1 Mar 1942. I-2 was sunk in the Bismarck Sea on 7 Apr 1944, by USS Saufley.

I-3 – sunk 9 Dec 1942 near Kamimbo Bay by PT-59.

I-4 – sank Høegh Merchant off Oahu 14 Dec 1941, Ban Ho Guan off Bali 28 Feb 1942 and USS Washingtonian off Eight Degree Channel 6 Apr 1942. I-4  was sunk in St. George's Channel on 21 Dec 1942, by USS Seadragon.

Junsen I Modified type (巡潜I型改, Cruiser submarine Type I Modified) (I-5-class) submarine was similar to the Type J1, but with facilities for one aircraft.

I-5 – possibly sunk 19 July 1944 off Guam by USS Wyman.

Junsen II type (巡潜II型, Cruiser submarine Type II) (I-6-class) submarine was similar to the I-5 class, but with a catapult for aircraft.

I-6 – sank Clan Ross in the Arabian Sea on 2 Apr 1942, and Bahadur in the Arabian Sea on 7 April 1942. I-6 was accidentally rammed and sunk 16 June 1944 off Hachijō-jima by Toyokawa Maru.

Junsen III type (巡潜III型, Cruiser submarine Type III) (I-7-class) submarines combined the benefits of the Type J2 and the Kaidai V (KD5). This type later led to the Type A, Type B, and Type C submarines.

I-7 – sank Merkus off Cocos Island on 4 Mar 1942, Glenshiel in the Indian Ocean on 3 Apr 1942, and USS Arcata off Unalaska on 14 July 1942. I-7 was damaged by gunfire off Kiska 22 June 1943 from USS Monaghan and ran aground on the Twin Rocks and was scuttled on 23 June 1943.

I-8 – sank Tjisalak on 26 Mar 1944, in the Indian Ocean and Jean Nicolet in May 1944. I-8 was sunk off Okinawa on 31 Mar 1945, by USS Morrison.

Type A or Junsen Type A type (甲型 or 巡潜甲型, (Cruiser submarine) Type A) (I-9-class) submarines were large seaplane-carrying submarines, with communication facilities to allow them to operate as command ships for groups of submarines. The type was also equipped with a hangar for one aircraft.

I-9 – sunk 14 June 1943 off Kiska by USS Frazier.

I-10 – sunk 4 July 1944 off Saipan by USS David W. Taylor and USS Riddle.

I-11 – missing south of Funafuti after 11 Jan 1944. Possibly struck a mine laid by USS Terror.

Type A Modified 1 or Junsen Type A Modified 1 type (甲型改一 or 巡潜甲型改一, (Cruiser submarine) Type A Modified 1) (I-12-class) submarine was similar to the Type A1, but with less powerful engines, giving the type slower surface speed but a longer range.

I-12 – sunk 13 Nov 1944 by USS Ardent and USS Rockford.

Type A Modified 2 or Junsen Type A Modified 2 type (甲型改二 or 巡潜甲型改二, (Cruiser submarine) Type A Modified 2) (Type A Mod.2, I-13-class) submarines was a large seaplane-carrying submarine, with hangar space for two aircraft. These giant submarines were originally of the A2 type, but following the cancellation of a number of I-400-class submarines, their design was revised after construction started to carry a second aircraft. The seaplanes were to be the Aichi M6A1 bomber carrying 800 kg bombs. The range and speed of these submarines was remarkable, 21,000 nmi (39,000 km; 24,000 mi) at 16 knots (30 km/h; 18 mph), but their underwater performance was compromised, making them easy targets.

I-13 — Sunk 16 July 1945 by USS Lawrence C. Taylor and aircraft from USS Anzio about 550 miles (890 km) east of Yokosuka. With 140 dead, the crew of I-13 was the largest loss of life in the IJN submarine force during the Second World War.

(Official USN Photo, located at the US National Archives, 80-G-701062)

I-14, 25 September 1945.

I-14 – Surrendered 27 Aug 1945. Sunk as target 28 May 1946 off Oahu by USS Bugara, reportedly to prevent it from falling into Soviet hands. Wreck found in 2009.

Type B or Junsen B type (乙型 or 巡潜乙型, (Cruiser submarine) Type B) (I-15-class) submarines were the most numerous type of submarines of the Imperial Japanese Navy during the Second World War. In total 20 were made, starting with I-15, the class ship. These were fast, very long ranged, and carried a single Yokosuka E14Y seaplane, located in a hangar in front of the conning tower, launched by a catapult.

Submarines I-17, I-19, I-21, I-23, I-25, I-26,I-27, I-28, I-29, I-30, I-31, I-32, I-33, I-34, I-35, I-36, I-37, I-38, I-39

I-15-class

I-15 – Sunk 10 Nov 1942 by USS Southard.

I-17– Sunk 19 Aug 1943 by HMNZS Tui and US Navy Kingfisher aircraft.

I-19 – Sank USS Wasp and USS O'Brien on 15 September 1942 and SS William K.Vanderbilt on 16 May 1943. The I-19 was depth-charged on 25 Nov 1943 by USS Radford.

I-21 – Sank SS Montebello on 23 Dec 1941, possibly sank USS Porter on 26 Oct 1942, SS Kalingo on 17 Jan 1943, SS Iron Knight on 8 Feb 1943, Mobilube on 18 Jan 1943, Starr King on 11 Feb 1943 and Cape San Juan on 12 Nov 1943. The I-21 went missing after 27 Nov 1943; possibly sunk off Tarawa by TBF Avengers on 29 Nov 1943.

I-23 – Missing off Oahu after 24 Feb 1942, likely due to a diving accident.

I-25 – Sunk 3 Sep 1943 off the New Hebrides by one or more US destroyers.

I-26 – Sank seven cargo ships, including the SS Cynthia Olson, the first US ship sunk after their entry into the Second World War. Crippled aircraft carrier USS Saratoga, and most famously finished off the already crippled light cruiser USS Juneau, killing the five Sullivan brothers. Sunk 26 Oct 1944 off Leyte by USS Coolbaugh or USS Richard M. Rowell.

I-27 – Sunk 12 Feb 1944 by HMS Paladin and HMS Petard.

‍I-28 – Sunk 6 Feb 1942 by USS Tautog.

I-29 – Sank six cargo and merchant ships and successfully completed several Yanagi missions. Sunk 26 July 1944 by USS Sawfish.

I-30 – Sunk by a mine near Singapore on 8 Oct1942. Salvaged between Aug 1959 and Feb 1960 and then scrapped.

I-31 – Sunk 13 May 1943 by USS Frazier.

‍I-32 – Missing after 23 Mar 1944. Possibly sunk on 24 Mar 1944 by USS Manlove.

‍I-33 – Sank at Truk 26 Sep 1942. Refloated 29 Dec 1942. Sank again 13 June 1944 in the Seto Inland Sea during trials. Salvaged between 23 July and 18 Aug 1953 and then scrapped.

I-34 – Sunk in the Malacca Straits by HMS Taurus. Salvaged in 1962.

I-35 – Rammed and sunk 23 Nov 1943 by USS

I-36 – Blown up and scuttled off the Gotō Islands on 1 Apr 1946 along with Ha-106 as part of Operation Road's End.

I-37 – Sunk 19 Nov 1944 off Palau by USS Conklin and USS McCoy Reynolds

‍I-38 – Missing after 7 Nov 1944. Possibly depth-charged on 13 Nov 1944 by USS Nicholas.

I-39 – Missing after 25 Nov 1943. Possibly sunk on 26 Nov 1943 by USS Boyd.

Type B Modified 1 or Junsen Type B Modified 1 type (乙型改一 or 巡潜乙型改一, (Cruiser submarine) Type B Modified 1) (I-40-class) submarines were externally similar to the Type B1, but with a high-tensile strength steel hull and diesel engines of a simpler design. In 1944, I-44 was modified as a Kaiten suicide torpedo carrier, armed with six kaitens.

I-40 – Missing off the Gilbert Islands after 22 Nov 1943.

I-41 – Sunk 18 Nov 1944 by USS Lawrence C. Taylor.

I-42 – Sunk 23 Mar 1944 by USS Tunny.

I-43 – Sunk 15 Feb 1944 by USS Aspro.

I-44 – Missing off Okinawa after 4 Apr 1945. Possibly sunk off Okinawa by a TBM Avenger of VC-92 on 29 Apr 1945.

I-45 – Sunk 29 Oct 1944 by USS Whitehurst.

Type B3 (I-54, I-56, I-58). Eighteen of the twenty-one Type B Modified 2 or Junsen Type B Modified 2 type (乙型改二 or 巡潜乙型改二, (Cruiser submarine) Type BModified 2) (I-54-class) submarines were cancelled in 1943 in favor of the TypeE submarine, leaving the I-54, I-56, and I-58. In 1944, I-56 and I-58 weremodified as Kaiten suicide torpedo carriers, each armed with four kaitens.

I-54 – Missing off Leyte after 23 October 1944. Possibly sunk 28 October 1944by USS Gridley and USS Helm.
I-56 – Possibly sank USS Snook[9] sometime after 8 April 1945. I-56 was herselflater sunk 18 April 1945 by USS Collett.

I-58 – Sank USS Indianapolis on 30 July 1945. I-58 surrendered on 2 Sep 1945, and was scuttled off the Gotō Islands on 1 Apr 1946 as part of Operation Road's End. The wreckage of I-58 was found in 2017.

Type C or Junsen C type (丙型 or 巡潜丙型, (Cruiser submarine) Type C) (I-16-class) submarines were based on the Junsen type submarine and developed from the Type KD6. This type, like the other Type C submarines, was utilized as mother ships for the Kō-hyōteki midget submarines and the Kaiten suicide torpedoes.

I-16 – Sank Susak on 6 June 1942, Aghious Georgios on 8 June 1942, Supetar on 12 June 1942, and Eknaren on 1 July 1942. Sunk 19 May 1944 by USS England.

I-18 – Sank Wilford on 8 June 1942, Mundra on 2 July 1942, and De Weert on 3 July 1942. Sunk 11 February 1943 by USS Fletcher.I-20 – Sank Johnstown on 5 June 1942, Christos Markettos on 8 June 1942, Mahronda on 11 June 1942, Hellenic Trader and Clifton Hall on 12 June 1942, Goviken on 29 June 1942, and Steaua Romana on 30 June 1942. Missing after 31 August 1943, probably sunk either on 1 September 1943 by USS Wadsworth or on 3 September 1943 by USS Ellet.I-22 – Sunk 6 October 1942 by a U.S. Navy PBY Catalina.I-24 – Sank Iron Chieftain on 3 June 1942. Rammed and sunk 11 June 1943 by USS PC-487.

Type C or Junsen C type latter batch (丙型 or 巡潜丙型 (後期型), (Cruiser submarine) Type C (latter batch)) (I-46-subclass) submarines were nearly identical to the Type C1 with the exception that the Type C2 lacked the capability to carry the midget submarines. I-47 and I-48 were converted to carry Kaiten manned suicide attack torpedoes.

I-46 – Missing after 26 Oct 1944. Possibly sunk by USS Gridley and USS Helm on 28 Oct 1944.  Also reported sunk by a multi-destroyer gun action involving USS Saufley, USS Renshaw, USS Waller, and USS Pringle around 28 Nov 1944.

 I-47 – Sank USS Mississinewa on 20 Nov 1944. I-47 surrendered on 2 Sep 1945 and was scuttled off the Gotō Islands on 1 Apr 1946 as part of Operation Road's End. The wreck of I-47 was found in 2017.

I-48 – Sunk 23 Jan 1945 by USS Conklin.

Type C3 Modified or Junsen Type C Modified type (丙型改 or 巡潜丙型改, (Cruiser submarine) Type C Modified) submarines (I-52-class) were submarines of the Imperial Japanese Navy, designed and built by Mitsubishi Corporation, between 1943 and 1944, as cargo carriers. They were quite long and carried a crew of up to 94 officers and enlisted. They also had a long cruising range at a speed of 12 knots (22 km/h). The Japanese constructed only three of these during the Second World War (I-52, I-53 and I-55), although twenty were planned. They were among the largest submarines ever built to date, and were known as the most advanced submarines of the period.[citation needed] I-53 was converted to carry kaiten manned suicide attack torpedoes.

I-52 – Sunk during Yanagi (exchange) mission to Germany on 24 June 1944 by aircraft from USS Bogue 800 nautical miles (1,500 km; 920 mi) southwest of the Azores. She was carrying Japanese engineers and a cargo of rubber, gold, and quinine to Germany.

I-53 – Sank USS Underhill on 24 July 1945. I-53 surrendered on 2 Sep 1945 and sunk as a target off the Gotō Islands on 1 Apr 1946 by USS Nereus as part of Operation Road's End. The wreck of the I-53 was found in 2017.

I-55 – Missing after 13 July 1944. Possibly sunk by USS William C. Miller on 14 July 1944. Sinking also credited to USS Reynolds and USS Wyman on 28 July 1944.

2,184 tonnes, The official designation of the submarine was Type C (Hei) submarine.

Type D1 ((潜)丁型, (Submarine) Type D) or Sen'yu(-Dai) type (潜輸(大)型, Transport submarine (large) type) (I-361-class) and Sen'yu Modified type (潜輸改, Transport submarine Modified) (I-372-class) submarines were based on the U-155. This type was designed as transport submarines with torpedoes for self-defense. Five of the submarines — I-361, I-363, I-366, I-367, and I-370 — were later modified to serve as kaiten suicide attack torpedo carriers, each armed with five kaitens.

Submarine I-361, I-362, I-363, I-364, I-365, I-366, I-367, I-368, I-369, I-370, I-371, I-372.

1,440 tonnes. The official designation of the submarine was Type D (Tei) submarine.

I-361 – Sunk southeast of Okinawa on 31 May 1945, by aircraft from USS Anzio.

I-362 – Sunk in eastern Caroline Islands on 14 Jan 1945, by USS Fleming.

I-363 – Sunk by mine off Miyazaki on 29 Oct 1945. Salvaged and scrapped on 26 Jan 1966.

I-364 – Sunk east of Honshu on 16 Sep 1944, by USS Sea Devil.

I-365 – Sunk southeast of Yokosuka on 29 Nov 1944, by USS Scabbardfish.

I-366 – Blown up and scuttled off the Gotō Islands on 1 Apr 1946 as part of Operation Road's End.

I-367 – Blown up and scuttled off the Gotō Islands on 1 Apr 1946 as part of Operation Road's End.

I-368 – Sunk west of Iwo Jima on 26 Feb 1945, by aircraft from USS Anzio.

I-369 – Surrendered on 30 Aug 1945 and scrapped at Yokosuka in 1946.

I-370 – Sunk near Iwo Jima on 26 Feb 1945, by USS Finnegan.

I-371 – Sunk in Bungo Strait on 24 Feb 1945, by USS Lagarto.

I-372 – Sunk at Yokosuka on 18 July 1945, by aircraft from Task Force 38.

Type D2 Modified ((潜)丁型改, (Submarine) Type D Modified) (I-373-class) submarine was designed as a tanker submarine based on the Type D1 but with no torpedoes.

I-373 – sunk in the East China Sea on 14 Aug 1945, by USS Spikefish. I-373 was the last Japanese submarine sunk in the Second World War.

Kiraisen type 4 (機雷潜型, Minelaying submarine) (I-121-class), the only Japanese minelayer submarines, were near-copies of the First World War German minelayer submarine UB-125. Originally numbered I-21, I-22, I-23, and I-24, they were renumbered I-121, I-122, I-123, and I-124, respectively, in 1938. This type saw front-line service during the Second Sino-Japanese War and the first half of the Second World War, modified to add seaplane refueling to their capabilities, but surviving units were relegated to training duties in September 1943 due to their growing obsolescence.

I-21/I-121 – Surrendered in Sep 1945 and scuttled in Wakasa Bay along with Ro-68 and Ro-500 on 30 Apr 1946. Wreck found in 2018.

‍1,142 tonnes. The official designation of the submarine was Kiraisen-type submarine.

I-22/I-122 – Sunk in the Sea of Japan 9 June 1945 by USS Skate.

I-23/I-123 – Sunk off Savo Island 29 Aug 1942 by USS Gamble.

I-24/I-124 – Sank Hareldawns off Luzon on 10 Dec 1941. Sunk off Darwin 20 Jan 1942 by HMAS Deloraine. I-124 was the first IJN warship sunk by the Royal Australian Navy.

Sen-Ho type (潜補型, Submarine tanker) (I-351-class) tanker/transport submarine.

I-351 – sunk 14 July 1945 in the South China Sea by USS Bluefish. 3,512 tonnes. The official designation of the submarine was Senho-type submarine.

Sentoku type (潜特型, Special type submarine) (I-400-class) displaced 5,223 tons surfaced and measured 400 ft 3 in (122.00 m) overall. They had a figure-eight hull shape for additional strength to handle the on-deck hangar for housing the three Seiran aircraft. In addition, they had four anti-aircraft guns, a large deck gun as well as eight torpedo tubes from which they could fire the 21-inch (533 mm) Type 95 torpedo. Three of the Sentoku were built (I-400, I-401, and I-402). Each had four 1,825 horsepower (1,361 kW) engines and range 37,500 nmi (69,400 km) at 14 knots (26 km/h).

The submarines were also able to carry three Aichi M6A Sei ran aircraft, each carrying an 800 kg (1,800 lb) bomb 550 nautical miles (1,020 km) at 360 mph (580 km/h). To fit the aircraft in the hangar the wings of the aircraft were folded back, the horizontal stabilizers folded down, and the top of the vertical stabilizer folded over so the overall profile of the aircraft was within the diameter of its propeller. A crew of four could prepare and get all three airborne in 45 minutes launching them with a 120-foot (37 m) catapult on the fore deck of the giant submarine.

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(USN Photo)

I-401 (伊号第四百一潜水艦, I-gō-dai yon-hyaku-ichi-sensuikan) was an Imperial Japanese Navy Sentoku-type (or I-400-class) submarine commissioned in 1945 for service in the Second World War. Capable of carrying three two-seat Aichi M6A1 "Seiran" (Mountain Haze) float-equipped torpedo bombers, the Sentoku-class submarines were built to launch a surprise air strike against the Panama Canal. Until 1965, the Sentaku-type submarines — I-401 and her sister ships I-400 and I-402 — were the largest submarines ever commissioned. I-400 – Surrendered 27 Aug 1945. Sunk as a target off Pearl Harbor on 4 June 1946 by USS Trumpetfish, reportedly to prevent it from falling into Soviet hands. Wreck found in 2013.

(HawkeyeUK Photo)

Aichi M6A1 Seiran, c/n 1600228, on display in the NASM Udvar Hazy Center. The M6A was designed to be operated entirely from an I-400 class submarine and could be used either as a dive bomber or a torpedo bomber. The prototype first flew in November 1943 and the first production aircraft was completed in October 1944. The name ‘Seiran’ translates as ‘Clear Sky Storm’, but the type was never encountered in combat and did not get allocated an Allied reporting name. The first operational mission was to have been an attack on the Gatun Locks of the Panama Canal, to cut off the American supply route. Two submarines, the I-400 and I-401, sailed on 23rd July 1945 carrying six Serians between them, with the aircraft reportedly painted in US markings. The Japanese surrendered before the attack took place and the aircraft were destroyed to prevent capture. This is the only surviving example of the type and is the last of the 28 aircraft built. She was surrendered to American occupation forces in Yokosuka by Lt. Kazuo Akatsuka of the Imperial Japanese Navy, who flew the aircraft from Fukuyama. It was shipped to the United States and became one of a large number of aircraft stored for museum use, officially being handed over to the Smithsonian Institute in 1960. Restoration began in June 1989 but having previously spent many years outside she was in a poor state and the project was not completed until February 2000. She is seen on display in the Steven F. Udvar Hazy Center as part of the National Air and Space Museum. Washington Dulles International Airport, Chantilly, Virginia

(Official USN Photo, located at the US National Archives, 80-G-345189)

I-401, 13 September 1945. I-401 – Surrendered 29 Aug 1945. Sunk as a target off Pearl Harbor on 31 May 1946 by USS Cabezon, reportedly to prevent it from falling into Soviet hands. Wreck found in 2005.

(Official USN Photo, located at the US National Archives, 80-G-345187)

I-401, 13 September 1945.

(Official USN Photo, located at the US National Archives, 80-G-345180)

I-402 – Surrendered in Sep 1945. Sunk as a target (along with Ha-201) 16 nmi off Kinai Island on 1 Apr 1946 by USS Everett F. Larson and USS Goodrich as part of Operation Road's End. Wreck located in 2015. 6,560 tonnes. The official designation of this submarine was Sentoku type Submarine.

(U.S. Naval History and Heritage Command Photo NH 97841)

The U.S. Navy submarine tender USS Euryale (AS-22) at Sasebo, Japan, in November 1945. She has three large Japanese submarines alongside. They are (from inboard to outboard): I-401, I-14 and I-400.

I-14, 25 September 1945.

(Official USN Photo, located at the US National Archives, 80-G-701060)

Ex-IJN submarines I-14 (centre) and I-400 at Sagami Bay, 25 September 1945.

(Official USN Photo, located at the US National Archives, 80-G-701061)

Ex-IJN submarines I-14 (centre) and I-400 at Sagami Bay, 25 September 1945.

With postwar relations with the Soviet Union deteriorating rapidly and concerns growing in the United States that under postwar agreements the Soviets would demand access to the captured Japanese submarines that would provide the Soviet Navy with valuable information about advanced Japanese submarine designs, the U.S. Navy issued orders on 26 March 1946 to sink all captured Japanese submarines. Accordingly, the U.S. Navy sank I-401 as a target in tests of the Mark 10 Mod 3 exploder off Pearl Harbor on 31 May 1946. She sank by the stern at 10:59 at 21°1′N 158°07′W after the submarine USS Cabezon (SS-334) hit her with two Mark 18 torpedoes.

‍Sentaka(-Dai) type (潜高(大)型, High-speed submarine (large) type) (I-201-class) submarines were modern design, and known as Sentaka (From Sen, abbreviation of Sensuikan, "Submarine", and Taka, abbreviation of Kōsoku, "High speed"). Three were built, I-201, I-202, and I-203 (I-204 to I-208 were not completed).

They displaced 1,070 tonnes, had a test depth of 360 feet (110 m), and were armed with four torpedo tubes and Type 96 25 mm (0.98 in) guns in retractable mounts to maintain streamlining. These submarines were designed for mass production. They were high-performance boats, with streamlined all-welded hulls and a high battery capacity supplying two 2,500 hp (1,900 kW) motors, which had nearly double the horsepower of the German-designed MAN diesels. The submerged speed was 19 knots (35 km/h), more than double that achieved by contemporary American designs. They were equipped with a snorkel, allowing for underwater diesel operation while recharging batteries.

I-201 – Surrendered 2 Sep 1945. Sunk as a target off Pearl Harbor on 23 May 1946 by USS Queenfish, reportedly to prevent it from falling into Soviet hands. Wreck found in 2009 along with that of I-14.

I-201 off Sasebo, Japan, on 9 Nov 1945.

I-201.

I-202 – Handed over to the Allies on 30 Nov 1945. Scuttled by the US Navy off the Gotō Islands on 5 Apr 1946 to avoid trouble between Britain and the Soviet Union (as both nations wanted to acquire the submarine).

I-203 – Surrendered 2 Sep 1945. Sunk as a target off Pearl Harbor on 21 May 1946 by USS Caiman.

I-204 – Was 90% complete. Sunk by air raid on 22 June 1945. Salvaged and scrapped at Kure in February to May 1948.

I-205 – Was 80% complete. Sunk by air raid on 28 July 1945. Salvaged and scrapped at Kure in May to August 1948.

I-206 – Was 85% complete. Construction stopped 26 Mar 1945. Scrapped at Kure October 1946 to January 1947.

I-207 – Was 20% complete. Construction stopped 17 Apr 1945. Scrapped at Kure April to May 1946.

I-208 – Was 5% complete. Construction stopped 17 April 1945. Scrapped at Kure April to May 1946 with I-207.

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