The tunnel is part of the Norwegian County Road 5236 which connects the island of Bjorøy in the municipality of Øygarden to the mainland near Håkonshella and Hilleren in the city-municipality of Bergen.

There were severe problems because the tunneling encountered an area of sandstone, causing a year's delay.

[2][3] Before the construction of the Bjorøy Tunnel, the geology of the area was thought to consist entirely of metamorphic basement rocks similar to those exposed on the surrounding islands.

The Jurassic sediments encountered in the tunnel included breccia and conglomerate in contact with the underlying gneisses and a sandstone with coal fragments, some of which was quite unconsolidated.

The committee was established on 6 January 1981 and concluded that there were three alternative possibilities to build a fixed link to Bjorøy: a bridge from the island over Søre Steinsundet via Vestre Steinsundholmen, Kjerringholmen and Kaggen to Søre Snekkevik on Litlesotra; a tunnel under Vatlestraumen to Håkonshella; or a bridge over Vatlestraumen to Håkonshella or Kongshaug.

All three included a road connection to Tyssøy, with the bridge proposals costing 16 million kr for the Tyssøy connection, and the tunnel having a cost of 4 million kr, in part because the earthworks volume from the tunnel could be used to build a mole with a short bridge.

[10] The plans were presented to Johan J. Jakobsen, Minister of Transport and Communications,[10] and cooperation was started with the Norwegian Public Roads Administration to find a suitable connection to Tyssøy, so that they could also take advantage of the tunnel.

In 1987, Kaare Hartman joined the committee and proposed that the tunnel be built with borrowed money, guaranteed by land-owners on the islands, and repaid using tolls.

Four land-owners made a guarantee for NOK 9 million, with a judicial registration covering an area of 347 hectares (860 acres).

[16] The plans were at first nearly discarded by the administration, as they felt it was impossible for a community of 400 people to finance such a large project without other grants.

A new estimate was made, which increased the price by NOK 10.3 million; however, Hordaland Public Roads Administration protested, stating that it would give an inferior road technically, that the existing development plans permitted the construction, and that the noise would not exceed the permitted limits.

The decision was appealed by lawyers representing the local community, but this was rejected by Hordaland County Governor on 30 August 1993.

[28] An agreement was made with Selmer, whereby they would charge NOK 59,422,500 and take the risk of the project, including any expenditures for unknown geological conditions or similar costs increases.

[28] The original construction consisted of blasting from Bjorøy, but by January 1994 there were problems with water leaks through cracks.

This caused extra work to be done on the exterior to the tunnel, and costs had increased by several tens of millions of kroner.

Geological engineers stated that there was no known solution to overcoming the problem, and that if the contractor had blasted into the area, the tunnel would have been filled with sand and water within minutes.

A technical committee was established, and on 16 December they recommended the use of cement injection combined with a ring of drainage holes around the tunnel before blasting.

On 22 January 1996, the tunnel company agreed to advance the construction costs and collect it from the tolls, with Sund Municipality guaranteeing for the debt.

[43] The contract for the construction of the bridge to Tyssøy was announced on 20 August 1996,[44] and was won by NCC Eeg-Henriksen Anlegg, who wanted NOK 8.5 million for the job.

[49][50] On 19 January 2004, the freight ship Rocknes ran aground on the unmarked underwater bank of Revskolt in Vatlestraumen, located above the tunnel.

In an attempt to avoid similar incidents occurring again, the Norwegian Coastal Administration started in May 2012 to blast away the bank, increasing the depth from 9 to 14 meters (30 to 46 ft).

The project was highly controversial amongst the islanders and the plans were approved by only a single decisive vote in the municipal council.

Calculations conducted by the Coastal Administration conclude that there is no chance of this occurring, as the blasting is taking place 65 meters (213 ft) above the tunnel.