The tunnel's length would depend upon the route taken; the shortest distance across would have a submarine length of 50 km, making it the longest undersea tunnel in the world. The project is largely being pushed forward by the mayors of Tallinn and Helsinki, Edgar Savisaar and Jussi Pajunen respectively. Both cities have promised €100,000 for preparatory studies, though the relevant ministries of each country have refused to grant any funding. An application is now planned to the EU to gain the additional funds needed for a comprehensive survey, estimated to cost between €500,000 and €800,000. On 13 January 2009, newspaper reports suggested the application to the EU, through the Interreg programme, for comprehensive surveys had been denied. An expert at the City of Helsinki's International Affairs department suggested this may have been because of political tension within Estonia, between the national administration and the City of Tallinn, both controlled by rival political groups. Nevertheless, both cities are said to be considering funding the surveys themselves.
The initial cost of the tunnel itself varies, from around one billion Euros for a freight-only tunnel, to many billions of Euros if passengers were to travel in it. The economic benefits would be significant, both in terms of increased connections and economic integration between the two cities (Copenhagen and Malmö have been offered as examples), but also in a wider context of convenient passenger train connections between Southern Finland and the Baltic States, and a fixed link for freight from across Finland on to the under-construction Rail Baltica, thus providing a rail freight connection with the rest of Europe. Geopolitically, the tunnel would connect two close but separated parts of the European Union in an environmentally friendly way, removing the need to travel through Russia, or to use air or sea transport.