On June 14, 2024, the governments of Finland and Estonia finalized the construction plan for the Helsinki Port Tunnel. The purpose of the tunnel's construction is to improve traffic at Helsinki South Harbour and make the area more livable.

One of the main reasons for choosing to build a tunnel was to protect the ecological environment along the route and to provide habitat for local flora and fauna, including the Siberian flying squirrel and the endangered Depressaria chaerophylli moth.