It is separated from Abel Island to the east-northeast by the seven-nautical-mile-wide (thirteen-kilometre) strait Lydiannasundet, and from Svenskøya to the west-southwest by Rivalensundet (15 nmi or 28 km wide).

At the southern side of Kongsøya is the wide open bay Breibukta, with several islets and skerries.

[4] At the southern side of the island, northeast of Kapp Altmann, is the long beach Snøsporvstranda.

[2] The interior of the eastern side contains the plain Rundisflya, named by the circular glaciated area Rundisen.

[8] Kong Karls Land was possibly observed by whaler Thomas Edge in 1617.

In 1985 the whole Kong Karls Land, including Kongsøya, was totally protected against human traffic.

[2][9] Kong Karls Land is regarded the most important hibernating area for polar bears in Svalbard.