The Atlantic Ocean Tunnel () is an undersea tunnel that connects the city of Kristiansund (Gomalandet island) with the island of Averøya to the west in Møre og Romsdal county, Norway. The long tunnel reaches a depth of , making it one of the deepest undersea tunnels in the world. Construction began in 2006 and the tunnel opened on 19 December 2009, later than initially estimated. Breakthrough was in March 2009. Problems with water leaks caused delays and cost overruns.
The tunnel's name comes from its connection of two islands located at the open Atlantic Ocean, and will serve as an extension of Atlanterhavsveien (Atlantic Ocean road), a popular tourist attraction. Atlanterhavsveien road runs over a series small islands with views of sea, fjord, and mountains, connecting Averøya to the mainland near Molde.