The 8th Submarine Squadron of the Imperial Japanese Navy was based at Swettenham Pier, Penang, Malaya, until late 1944 during World War II.

On March 27 the German naval high command asked the Japanese to attack Allied convoys in the Indian Ocean.

The Japanese agreed on April 8 and shortly afterward, the IJN's 8th Submarine Squadron, 1st Division, was withdrawn from Kwajalein in the Marshall Islands and sent to Penang, Malaya.

The squadron's first operation was an Indian Ocean anti-shipping sweep by its 1st Division from Aden down the coast of East Africa to Madagascar.

During the sweep the auxiliary cruisers captured the Dutch tanker Genora 480 nautical miles (890 km; 550 mi) south-southeast of Diego Suarez, Madagascar, on 9 May 1942.

After the midget submarine ran aground, its crew — Lieutenant Saburo Akieda and Petty Officer Masami Takemoto — abandoned it and reached shore.

I-30 proceeded around the Cape of Good Hope to Lorient in occupied France, arriving there on 5 August 1942 and becoming the first Japanese submarine to reach German-held territory during World War II.

On October 13 she was returning from Europe to Japan when she struck a mine off Singapore and sank 3 nautical miles (5.6 km; 3.5 mi) east of Keppel Harbour.

From September to November 1942 the squadron's submarines sank another 40 ships totaling 224,500 gross register tons in the Indian Ocean.

The Army had set up a school in Penang under Captain Mahmood Khan Durrani for training Indian agents who were in turn landed in India by the squadron's submarines.

On her return voyage in September or October, I-8 was attacked by Allied aircraft off the west coast of Africa but sustained no damage.

Leaving Singapore in December, she reached Japan safely and returned to Penang in early 1944 with a new commander, Tatsunosuke Ariizumo.

The U.S. Navy submarine USS Swordfish (SS-193) sank her during her return journey in the Bashi Channel south coast of Formosa on 26 July.

While underway, she intercepted and sank the troopship SS Khedive Ismail, but was in turn caught and sunk between the Maldive Islands and Addu Atoll by the convoy's escorts HMS Paladin and Petard.

On March 18 I-165 under Lt Cdr Shimizu Tsuruzo torpedoed and sank the 3,916-ton British armed merchant Nancy Moller at 02-14N, 78-25E.

Initially the Commander Noboru Ishizaki held the rank of captain, but eventually was promoted to rear admiral on November 1, 1942.