Adventfjorden (Advent Bay) is a 7 km long and 4 km wide bay running south-eastwards from the southern side of Isfjorden, on the west coast of Spitsbergen in Svalbard. The name represents a corruption of Adventure Bay - probably named after the Hull-built whaleship Adventure, which operated in Isfjorden in 1656. The fjord was originally[when?] known as Klass Billen Bay. At the head of Adventfjorden is Adventdalen (Advent Valley).

Adventfjorden lies on the southern side of Isfjorden on Spitsbergen's west coast.

The former mining-camp of Longyearbyen (now Svalbard's main town) lies on the fjord's southwestern shore, while another former mining-camp, Hiorthhamn, is located on its northeastern shore.



Coordinates: 78°10′N 15°40′E / 78.167°N 15.667°E / 78.167; 15.667