[2] The Iki Islands are volcanic in origin: they are the exposed and eroded basaltic summit of a massive Quaternary stratovolcano last active over 600,000 years ago.

[4][verification needed] The archipelago is approximately 20 kilometres (11 nmi) north-northeast of the Kyushu coast at its closest point and southeast of the Tsushima Islands.

[4][verification needed] The Iki Islands have been inhabited since the Japanese Paleolithic era, and numerous artifacts from the Jōmon, Yayoi and Kofun periods have been found by archaeologists, indicating continuous human occupation and activity.

[6] In the Chinese Wèizhì Wōrén chuán (Japanese 魏志倭人伝, Gishi Wajinden), part of the Records of the Three Kingdoms dating from the third century, mention is made of a country called “Iki”, (一支国, Iki-koku), located on an archipelago east of the Korean Peninsula.

Archaeologists have tentatively identified this with the large Yayoi period settlement of Harunotsuji, one of the largest to have been discovered in Japan, where artifacts uncovered indicate a close contact with the Japanese islands and the Asian mainland.

[8] The islands were organized as Iki Province under the Ritsuryō reforms in the latter half of the seventh century, and the name Iki-no-kuni appears on wooden markers found in the imperial capital of Nara.

Afterwards, the islands came under the rule of the Matsura clan, who developed trade and commercial relations between Goryeo in Korea, Tsushima, Iki and Kyushu.

On November 18, 1948, Lt. William Downham, from the USAF 36th Fighter Group stationed at Ashiya Air Field, experienced engine failure in his North American P-51 Mustang while patrolling the Korea Strait between Japan and the Korean Peninsula.