The E8 between the mainland and Tromsøya runs 3.5 kilometres under the Tromsøysundet strait in Troms. The tunnel opened in 1994 and has two bores, one for each direction.

For a long time it was Norway's only undersea road tunnel with two bores, and it has 15 cross passages between them. Inside, roundabouts were blasted into the rock, connected to the tunnel system towards Kvaløya. Oncoming traffic in tunnels is rare here, which makes the daily commute safer.

Tromsø got its first fixed crossing of the sound in 1960 with the Tromsø Bridge, but it filled up as the city grew. The 1994 tunnel doubled the capacity, and quickly became central to the growth of Kvaløya. When it closes at rush hour, Tromsø almost stands still, so check the status.