|The tunnel entrance on the Tromsøya-side in Breivika with UNN in the background.|
|Location||Tromsø, Troms, Norway|
|Opened||3 December 1994|
|Length||3,500 m (11,500 ft; 2.2 mi)|
|Number of lanes||4 (two each direction)|
|Lowest elevation||−102 metres (−335 ft)|
The Tromsøysund Tunnel (Norwegian: Tromsøysundtunnelen) is an undersea highway tunnel under the Tromsøysundet strait, connecting the island of Tromsøya with the mainland in the city of Tromsø in Troms county, Norway.
The tunnel is part of European route E08, (whose northern terminus is on the island itself) and it consists of 2 tubes, each with two driving lanes. The two tubes are not equal in length; one tube is 3,500-metre (2.2 mi) long and the other is 3,386-metre (2.1 mi) long. The lowest point in the tunnels is 102 metres (335 ft) below sea level, and the maximum grade is 8.2%. The two tubes are linked by 15 service-tunnels.
The tunnel opened on 3 December 1994 to relieve Tromsøya's only other mainland connection, the Tromsø Bridge, which had been plagued by severe traffic congestion for more than a decade. The tunnel is located to the north of the bridge; on the island side it emerges just below the University of Tromsø and the University Hospital of North Norway, both major sources of traffic between the island and the mainland; on the mainland side it emerges at Tomasjord which is centrally located between the densely popluated suburbs of Tromsdalen and Kroken.
- Media related to Tromsøysundtunnelen at Wikimedia Commons