Designed as a submarine aircraft carrier, she was commissioned in 1941 and supported the attack on Pearl Harbor, operated in the Indian Ocean — including support for the 1942 midget submarine attack on Diego Suarez — and in the New Caledonia and New Zealand areas, and took part in the Guadalcanal campaign and Marianas campaign before she was sunk in 1944 during her seventh war patrol.

[5] That day, the 6th Fleet commander, Vice Admiral Mitsumi Shimizu, held a meeting with the commanding officers of the submarines of Submarine Squadron 3 aboard his flagship, the light cruiser Katori, and his chief of staff briefed them on plans for Operation Z, the upcoming surprise attack on Pearl Harbor in Hawaii.

[5] As Japanese military forces began to deploy for the opening Japanese offensive of the war, I-10, with an embarked Watanabe E9W1 (Allied reporting name "Slim") floatplane, departed Yokosuka, Japan, on 16 November 1941, with orders to conduct a reconnaissance of areas in the vicinity of Fiji and the Samoan Islands, including Tutuila in American Samoa.

[5] Heading toward Hawaii after leaving the waters around American Samoa, I-10 arrived in a patrol area 1,300 nautical miles (2,400 km; 1,500 mi) south of Oahu on 7 December 1941, the day the Japanese attacked Pearl Harbor.

[5] While 700 nautical miles (1,300 km; 810 mi) southeast of Hawaii after dark that evening, she fired one torpedo at the Panamanian 4,430-gross register ton motor vessel Donerail, which was on a voyage from Suva to Vancouver, British Columbia, Canada, with a cargo of sugar and pineapples.

[5] As Donerail′s crew abandoned ship, one shell struck her starboard lifeboat while it still hung in its davits, completely destroying it and killing everyone in it.

[5] On 12 December 1941, I-10 was reassigned to the Advance Force, and that day she received orders to proceed to the United States West Coast and patrol in an area off San Diego, California.

[5] During the detachment′s voyage, 16 United States Army Air Forces B-25 Mitchell bombers launched by the aircraft carrier USS Hornet (CV-8) struck targets on Honshu in the Doolittle Raid on 18 April 1942.

[14] The detachment received orders from the 6th Fleet that day to divert from its voyage and head northeast, passing north of the Bonin Islands, to intercept the U.S. Navy task force that had launched the strike.

The Imperial Japanese Army transport Urajio Maru mistakenly opened gunfire on her during her voyage, but she avoided damage and arrived at Penang safely on 25 April 1942.

[5] On 27 April, the rest of the "A" Detachment arrived at Penang, where the seaplane carrier Nisshin — which had undergone modifications allowing her to carry Type A midget submarines — rendezvoused with it.

[14] I-10′s Yokosuka E14Y1 (Allied reporting name "Glen") floatplane began reconnaissance flights over ports in South Africa by reconnoitering Durban on 20 May 1942,[5][12][14] where its crew found no targets of importance.

Although challenged from the ground during the flight, the aircraft escaped after its radioman bought time by transmitting a false recognition signal in response.

[5] Still in the Mozambique Channel south of Beira on 30 June, she torpedoed the American 6,737-gross register ton armed steamer SS Express, which was on a voyage from Bombay to Cape Town with a cargo of manganese ore, jute, and leather.

[5] Eleven members of Express′s crew and two personnel of her United States Navy Armed Guard drowned after abandoning ship when their boat was swamped in heavy seas.

[5] I-10 surfaced and sank Hartismere with gunfire at 18°00′S 041°22′E / 18.000°S 41.367°E / -18.000; 41.367, and Hartismere′s crew and gunners made it to shore in her lifeboats at Caldera Point on the coast of Portuguese East Africa.

[5] I-10′s final victim of the Indian Ocean operation was the 4,427-ton Dutch armed merchant ship Alchiba, which was on a voyage from Durban, South Africa, to London via Aden with a cargo of 4,000 tons of ammunition.

[5] On 24 November 1942 she got underway from Truk to patrol off San Cristobal in support of a midget submarine attack against Allied shipping in Lungga Roads off the north coast of Guadalcanal.

[5] After dark on 24 January, she launched her floatplane for a reconnaissance flight over the Nouméa area — at a time when United States Secretary of the Navy Frank Knox and the Commander-in-Chief of the United States Pacific Fleet, Chester W. Nimitz, were in Nouméa for a Commander, South Pacific Area conference[5] — and at 01:00 on 25 January its crew reported seeing several battleships, cruisers, destroyers, and transports in the harbor.

[5] Gulfwave′s crew and United States Navy Armed Guard detachment suffered no casualties, and the tanker made port at Suva in the Fiji Islands under her own power.

[5] With them complete, she departed Sasebo on 17 May 1943 and made for the Seto Inland Sea for workups and where from 17 to 19 May she engaged in refueling exercises in the Iyo-nada with the submarine I-8,[5] which had been selected to carry out a Yanagi mission, a round-trip voyage between Japan and German-occupied France[19] I-10 arrived at Kure on 26 May 1943.

[5] I-10 took Alcides′s master, radio officer, and second mate aboard, and they remained prisoners of war in Japan until freed by American forces on 29 August 1945.

[5] At about 16:30 on 1 October 1943, I-10 sighted an Allied convoy in the Gulf of Aden heading west at 10 knots (19 km/h; 12 mph) and set out in pursuit.

[5] She fired three torpedoes at the 4,836-gross register ton Norwegian armed merchant ship SS Storviken, which was carrying a cargo of coal from Mombasa in British East Africa to Aden.

[5] When 140 nautical miles (259 km; 161 mi) northwest of Cape Guardafui, the northernmost tip of British Somaliland, at 05;10 on 5 October, she fired three torpedoes at overlapping targets at a range of 6,340 yards (5,800 m), then dived to 390 feet (119 m).

[5] The British whaling ship Okapi and two Royal Air Force Catalina flying boats rescued her other 37 survivors.

[5] I-10 suffered three killed and two wounded and sustained minor damage during the first day of the raid, but she and the submarines Ro-36 and Ro-42 put to sea on 17 February in an attempt to intercept the attacking ships.

[5] On 4 March 1944, however, she suffered damage in a depth-charge attack in the Pacific Ocean east of Mili Atoll and was forced to abort her patrol.

[5] On 24 June 1944, the Combined Fleet ordered Owada to evacuate Takagi and his staff from their headquarters on the eastern coast of Saipan.

At 17:02 on 4 July 1944, U.S. Navy Task Group 50.17, with six tankers and the escort carrier USS Breton (CVE-23), was refueling at sea 110 nautical miles (200 km; 130 mi) northeast of Saipan when the destroyer escort USS Riddle (DE-185) gained sound contact on a submerged submarine bearing 250 degrees at a range of 1,900 yards (1,740 m).