The tunnel is projected to cost NOK 4.6 billion, and is being financed through Oslo Package 1, with part of the funding coming from the city's toll ring. The project includes an additional 8.0 kilometres (5.0 mi) of roads, 5.7 kilometres (3.5 mi) of pedestrian and cyle paths and 3.5 kilometres (2.2 mi) of bus lanes. The project will create a 6.0 kilometres (3.7 mi) continuous tunnel from Framnes (at the Kiel ferry terminal) to Ryen. The connection with the Festning Tunnel will require a 100 metres (330 ft) sinking of the latter, and it will have a basement built under it.
The Bjørvika Tunnel will be the first immersed tunnel in Norway. The modules are built in Askøy, and shipped for five days to reach Oslo. Each of the six modules is 112.5 metres (369 ft), 28 to 43 metres (92 to 141 ft) wide and 10 metres (33 ft) high. Production started in 2005, and the final module was delivered in 2008. The need for an immersed tunnel was caused by the 50 metres (160 ft) of clay on top of the bedrock. To allow sufficient gradient for a conventional bedrock tunnel, the tunnel would have needed to be several kilometres longer.