There is a plan to connect the Finnish and Estonian capitals through a 62-mile underwater rail tunnel. If accomplished, this would be the longest undersea tunnel in the world, surpassing the Seikan Tunnel in Northern Japan and the Channel Tunnel between the UK and France.
The project, first proposed over a decade ago, would go underneath the Gulf of Finland to link Northern Europe with the Baltic Area. This would effectively create a Helsinki-Tallinn metropolitan area for the twin cities, and reduce travel time, which is currently done mostly by ferry, from 2 hours to 30 minutes.
Although there are no concrete plans or a construction schedule yet, multiple feasibility studies have been carried out over the years, and a private company has even offered to build the tunnel with Chinese funding. The total cost would be around $16.8 billion (€15bn) and the estimated number of passengers crossing the Gulf of Finland would be 30 million by 2030, according to Railway Technology.
Project Background And Status

An undersea tunnel between Finland and Estonia has been discussed for more than ten years. In 2009, both governments proposed studies to assess its feasibility, and in 2015 a pre-feasibility report was published declaring that EU funding would be needed to cover an estimated €9-13 billion construction cost, with a possible starting date of 2030.
Between 2016 and 2018, a longer study was carried out with European funding, and in 2021, Finland and Estonia signed a Memorandum of Understanding stating cooperation in the transport sector in order to promote projects such as the Helsinki-Tallinn project. However, no concrete construction plans have been published yet, and when the project will come to fruition is still an open question.
In 2016, a similar project was proposed by the private company FINEST Bay Area Development, which was co-founded by Angry Birds developer Peter Versterbacka. Additionally to building the tunnel, this project proposed the creation of two artificial islands to house 50.000 people, according to Railway Supply. In this scenario, the funding would come from Chinese investors instead of the European countries and the European Union.
But Finland and Estonia have rejected this possibility, stating that the Helsinki-Tallinn tunnel must remain a state project, publically funded by the two countries and the European Union.
“We understand that it is clearly beyond the capabilities of Estonia and Finland to do this project alone, it requires co-financing from the EU. What lies ahead is that a lot of research needs to be done, but it makes sense to do it when we are on the road network and European co-financing is coming,” said to ERR News the Estonian Minister of Economic Affairs Taavi Aas.
Importance Of The Tunnel For A European Network

The Bay Area between Finland and Estonia is an important region of economic development, having the most unicorn companies (valued at $1 billion) per capita, according to Finest Bay Area. The metropolitan area created by uniting Helsinki and Tallinn would thus create a powerful economic hub between Finland and the Balkans.
Furthermore, creating this link would finally connect Northern Europe with Central Europe and the Balkans. Rail Baltica, a proposed high-speed rail connection between Warsaw and Helsinki, is planned to unite five countries across 870 km.
As a necessary step for this project, the Helsinki-Tallinn tunnel would have railways of standard European gauge. It would then become a part of the Trans-European Transport Network, a long-term railway project and a “key instrument for the development of coherent, efficient, multimodal, and high-quality transport infrastructure across the EU,” according to the European Commission.
If the tunnel is ever built, the old expression stating that “Finland is an island” would lose a great part of its meaning, and an integrated European rail network would take a step closer to realization.