Hailuoto causeway opened for traffic in June – GRK implemented one of Finland’s most significant transport infrastructure projects

The causeway between Hailuoto and the mainland opened for traffic at the end of June 2026. The project is one of the most significant transport infrastructure projects in Finland in recent years. A journey that previously depended on ferry services can now be completed by car in around eight minutes.

GRK was responsible for the construction of the project as part of an alliance. In addition to GRK, the Hailuoto project alliance included the designers A-Insinöörit and AFRY Finland, as well as the Finnish Transport Infrastructure Agency as the client.

Construction progressed as planned, and the causeway could be opened ahead of schedule without compromising on safety or quality.

"The completion of the Hailuoto causeway is proof of what can be accomplished when capable people work together towards a common goal. I'm especially proud of the how the alliance operated. The credit for this accomplishment goes to every employee, partner, client, designer, public authority and stakeholder involved. This is not the achievement of a single organisation – instead, it is the shared success of the entire alliance, which we can all be proud of," says Project Manager Timo Takala from GRK.

Marine conditions placed exceptional demands on the project

The construction of the Hailuoto causeway took place in exceptional marine conditions. The project involved constructing close to seven kilometres of embankment across the sea, along with two bridges that are among the largest in Finland. Construction was carried out in open sea, where strong winds, ice conditions, large variations in water levels and demanding marine logistics presented special requirements throughout the project.

Technically demanding work phases were carried out during the project, including bridge concrete pours lasting several days at a time. In spite of the challenging conditions, the project was implemented safely and efficiently from start to finish.

Close cooperation to complete a project that had been decades in the making

The causeway, which had been prepared for decades, has been a significant development project for the area. Its implementation required long-term and close cooperation between the client, designers and constructors throughout all phases of the project. A common goal and cooperating in accordance with the alliance model were key to the success of the project.

"The cooperation between the alliance members was on track right from the tendering phase and only improved as the project progressed. We were able to combine the decades of expertise of experienced professionals with the fresh ideas of young experts. This diverse competence base has enabled high-quality and innovative operations throughout the project," says Jaakko Mäkelä, Business Director, Civil Engineering and Paving at GRK.