It lies in Hinlopen Strait northeast of Cape Weyprecht on Spitsbergen.

The island has an hourglass shape with a north–south orientation, reaching an elevation of 16 meters (52 ft) above sea level on its south end and 18 meters (59 ft) on the north.

There are some unnamed rocks and islets lying off the island to the northwest.

The island was discovered in 1867 by the Swedish-Norwegian polar explorer Nils Fredrik Rønnbeck.

It is named after Sivert Kristian Tobiesen (1821–1873),[2] a Norwegian seal hunter that spent the winter on Bear Island.