Core samples showed that the tunnel would have to be built deeper than originally planned to avoid deposits. The tunneling was undertaken by NCC Eeg-Henriksen from the Føyno side and by the Norwegian Public Roads Administration from the Sveio side. Construction from Sveio started on 16 September 1997 and from Føyno on 6 March 1998. The tunnel was built at an average speed of per week, with the record being . The lowest point was reached on 5 May 1999 and the breakthrough took place on 2 September, five months before schedule. Sixty people participated in a course to master fear of tunnels organized by the toll company. When it opened, the tunnel was the longest and second-deepest subsea tunnel in Europe and Norway, after the Hitra Tunnel.