I-26 was an Imperial Japanese Navy B1 type submarine commissioned in 1941. She saw service in the Pacific War theatre of World War II, patrolling off the West Coast of Canada and the United States, the east coast of Australia, and Fiji and in the Indian Ocean and taking part in Operation K, preparatory operations for the Aleutian Islands campaign, and the Guadalcanal campaign, the Marianas campaign, and the Battle of Leyte Gulf. She was the first Japanese submarine to sink an American merchant ship in the war, sank the first ship lost off the coast of State of Washington during the war, damaged the aircraft carrier , sank the light cruiser , and was the third-highest-scoring Japanese submarine of World War II in terms of shipping tonnage sunk. Her bombardment of Vancouver Island in 1942 was the first foreign attack on Canadian soil since 1870. In 1944, I-26′s crew committed war crimes in attacking the survivors of a ship she sank. She was sunk in November 1944 during her ninth war patrol.

Construction and commissioning

Built by the Kure Naval Arsenal at Kure, Japan, I-26 was laid down on 7 June 1939 as Submarine No. 139. She was launched on 10 April 1940 and provisionally numbered I-27 that day, but she was renumbered I-26 on 1 November 1941. She was completed and commissioned on 6 November 1941.

Service history Pre-World War II On the day of her commissioning, I-26 was attached to the Yokosuka Naval District and assigned to Submarine Division 4 in Submarine Squadron 1 in the 6th Fleet, a component of the Combined Fleet. She departed immediately for work-ups in the Seto Inland Sea.

On 10 November 1941, as the Japanese armed forces began to deploy for the offensive that would begin the Pacific campaign of World War II, I-26 was assigned to the 6th Fleet Reconnaissance Unit and received orders to conduct a prewar reconnaissance of the Aleutian Islands area. She arrived at Yokosuka, Japan, on 12 November 1941, and began preparations for the mission, which called for I-26 to operate at the limits of her endurance. Rather than embark a floatplane, her crew filled her hangar with food because of a lack of space below for sufficient provisions. With modern Type 95 torpedoes in short supply, she instead loaded only ten old 6th Year Type torpedoes, seven fewer torpedoes than she was designed to carry.

I-26 departed Yokosuka at 15:00 on 19 November 1941 and set course for the Aleutians with orders to reconnoiter American naval bases there and report on the United States Navy presence in the area to the commander-in-chief of the Combined Fleet, Admiral Isoroku Yamamoto, by 5 December 1941, then proceed to a patrol area in the Pacific Ocean halfway between San Francisco, California, and Hawaii to observe and report any American reinforcements headed toward Hawaii from the United States West Coast. When she was from the Aleutians, she began a routine of operating submerged by day and on the surface only at night. After arriving in the Aleutians, she conducted a periscope reconnaissance of Attu, Kiska, and Adak between 26 and 28 November 1941 and of Dutch Harbor on Amaknak Island off Unalaska on 29 November. Finding no American naval presence in any of these areas, she headed for her Pacific patrol area, centered around . She received the message "Climb Mount Niitaka 1208" () from the Combined Fleet on 2 December 1941, indicating that war with the Allies would commence with the attack on Pearl Harbor on 8 December 1941 Japan time, which was on 7 December 1941 on the other side of the International Date Line in both Hawaii and I-26′s patrol area.

When off San Francisco on 6 December 1941, I-26 sighted the 2,140-gross register ton cargo ship , a lumber steamer under charter to the United States Army making and carrying a cargo of U.S. Army supplies from Tacoma, Washington, to Honolulu, Hawaii.Artfiberglass.com, The SS Cynthia Olson Under orders not to commence hostilities until 03:30 on 8 December Japan time — the anticipated time of the attack on Pearl Harbor, which was 08:00 on 7 December Hawaii time and 09:00 local time on 7 December in I-26′s patrol areaWebber (1975), pp. 13-14 — I-26 determined Cynthia Olson′s course and speed, pursued her until dark, then surfaced and moved ahead of her so as to be in position to attack her when hostilities began the next morning.

World War II First war patrol At dawn on 7 December 1941, I-26 found Cynthia Olson exactly where the submarine's crew expected to find her along her projected course. At 09:00 local time on 7 December, which was 08:00 on 7 December in Hawaii and 03:30 on 8 December in Japan and was only minutes after the attack on Pearl Harbor began, I-26 determined Cynthia Olson′s nationality, surfaced near her, and fired a warning shot. Cynthia Olson′s crew transmitted an SOS and abandoned ship in two lifeboats.Prange, p. 89. I-26 fired 18 rounds from her aft gun from a range of at Cynthia Olson, setting her ablaze.Nelson, p.208. Twenty minutes after opening fire, she received the message Tora! Tora! Tora! ("Tiger! Tiger! Tiger!"), indicating that the Pearl Harbor attack had achieved complete surprise. She submerged and fired a torpedo at Cynthia Olson from a range of , but it missed her astern because she still was underway. I-26 surfaced again and resumed fire, firing 29 more rounds over the next two hours before departing the area when Cynthia Olson finally rolled onto her side in a sinking condition some five hours after I-26 first attacked her. Cynthia Olson sank later on 7 December northeast of Hawaii at , the first American merchant ship lost after the entry of the United States into the war and the first American merchant ship sunk by a Japanese submarine.Harding, Stephen. (2010) "Voyage To Oblivion, A Sunken Ship, A Vanished Crew And The Final Mystery Of Pearl Harbor." Amberley Publishing; The American ocean liner picked up Cynthia Olson′s SOS from a considerable distance away and on 8 December the Japanese submarine came across her lifeboats and provided her survivors — 33 crewmen and two U.S. Army passengers — with food, but after that they were never seen or heard from again.

After the submarine reported sighting a aircraft carrier and two cruisers steaming east-northeast of Oahu on 9 December 1941, the commander of the 6th Fleet, Vice Admiral Mitsumi Shimizu, aboard his flagship, the light cruiser at Kwajalein Atoll in the Marshall Islands, ordered I-26 and all the other submarines of Submarine Squadron 1 except for those of the Special Attack Force serving as the mother ships for midget submarines to search for the ships. The search was unsuccessful.

On 14 December 1941, I-26 was among a number of submarines ordered to proceed to the U.S. West Coast to attack shipping. The same day, Japanese Imperial General Headquarters ordered the submarines to bombard the U.S. West Coast, and Vice Admiral Shimizu instructed I-26 and the submarines , , , , , , , and each to fire 30 rounds on the evening of 25 December, with the commander of Submarine Squadron 1, Rear Admiral Tsutomu Sato aboard his flagship I-9, in overall command of the bombardment. I-26 arrived in her assigned patrol area in the Strait of Juan de Fuca off Cape Flattery, Washington, near Seattle on 20 December 1941 and sighted several merchant ships, but could not make any attacks due to heavy seas and poor visibility. On 22 December, Admiral Yamamoto postponed the bombardment from 25 to 27 December, and on 27 December Rear Admiral Sato cancelled it entirely because of the frequency of coastal air and surface patrolsWebber (1975), pp. 14-15 and because the submarines tasked with carrying it out were very low on fuel. I-26 concluded her patrol with her arrival at Kwajalein on 11 January 1942 after 54 days at sea.

January–February 1942 While at Kwajalein, I-26 fueled and loaded provisions in company with I-15, I-17, and I-23. She also loaded modern Type 95 torpedoes for the first time in the war. One source asserts that she made a voyage to Yokosuka and back to Kwajalein during January 1942 for new equipment and training. While she was at Kwajalein, 46 U.S. Navy aircraft from the aircraft carrier raided Kwajalein and Wotje Atoll on 1 February 1942, sinking a transport, wounding Vice Admiral Shimizu and damaging a number of ships, including Shimizu's flagship Katori, the auxiliary submarine tender Yasukuni Maru, and I-23. Moored alongside I-23, I-26 attempted to open fire on the attacking planes with her 25-millimeter antiaircraft gun, but it malfunctioned, and instead she submerged and avoided damage. Two hours after the raid, the 6th Fleet ordered I-9, I-15, I-17, I-19, I-23, I-25, I-26, and the submarines and to find and attack Enterprise, but they had no success.

Operation K

On 3 February 1942, I-15, I-19, I-23, and I-26 were recalled to Kwajalein, and on 5 February they and I-9 were selected to participate in Operation K, which called for two Imperial Japanese Navy Kawanishi H8K1 (Allied reporting name "Emily") flying boats to fly from Wotje, stop at the French Frigate Shoals in the Northwestern Hawaiian Islands west-northwest of Oahu to refuel from submarines, then fly to Oahu to bomb Honolulu before returning to Wotje. I-9 was to take station halfway between Wotje and the French Frigate Shoals to act as a radio beacon for the aircraft, I-23 was to operate south of Pearl Harbor to provide weather reports and rescue the crews of any aircraft that were shot down, and I-15, I-19, and I-26 were to refuel the planes.

On 14 February 1942, I-15, I-19, and I-26 each had six fuel tanks for aviation gasoline installed in their hangars, and the three submarines departed Kwajalein on 20 February 1942 bound for the French Frigate Shoals. With I-26 remaining offshore in reserve, I-15 and I-19 arrived at French Frigate Shoals on 4 March 1942, where the two flying boats landed that evening. After refueling they took off again, made the seven-hour flight to Honolulu, dropped their bombs early on 5 March without achieving anything of importance, and returned to the Marshall Islands safely. With the operation complete, I-26 made for Yokosuka, Japan, where she arrived on 21 March 1942 and began repairs.

March–May 1942

While I-26 was in Drydock No. 5 at Yokosuka, 16 United States Army Air Forces B-25 Mitchell medium bombers launched from the aircraft carrier struck targets in Japan on 18 April 1942 in the Doolittle Raid. Some of I-26′s crew aboard her and ashore witnessed part of the raid, and one B-25 bombed and damaged the light aircraft carrier , which was undergoing conversion from the submarine tender Taigei in the adjacent Drydock No. 4.Webber (1975), p. 153. I-26 suffered no damage or casualties in the raid.

Second war patrol

As Japan made preparations to begin the Aleutian Islands campaign with landings on Attu and Kiska in the Aleutian Islands and an air strike on Dutch Harbor, I-26 got underway from Yokosuka at 13:00 on 16 May 1942 to begin her second war patrol, ordered to reconnoiter the Kodiak Island area off the coast of the Territory of Alaska and then raid shipping off Seattle. While she was at sea, she was reassigned to the Northern Force. She conducted a reconnaissance of Kodiak Island on 24 May 1942 and of Chirikof Island and Sitkanak Island on 26 May 1942. On 27 May 1942, I-25 launched a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane for a reconnaissance flight over Dutch Harbor, and I-26, which had no aircraft embarked, stood by to recover the aircraft in case I-25 was unable to.Morison, Vol. IV, p. 173.