Hailuoto Bridge: Project Updates, Map & Completion Date

Connecting an Island: The Story of Finland’s Hailuoto Causeway and Bridges

For decades, traveling to Hailuoto—the largest island in the northern Baltic Sea, located just off the coast of Oulu, Finland—meant relying on a weather-dependent road ferry. That logistical chapter closed when one of Finland’s most ambitious modern infrastructure projects officially opened to traffic: the Hailuoto Causeway and Bridge Project.

By replacing a slow boat ride with a direct road link, this engineering marvel has permanently transformed daily life, travel, and tourism for the region.

Anatomy of the Project

While discussions and feasibility studies for a fixed link began as far back as the 1980s, the project finally gained momentum with the creation of a specialized construction alliance. Ground broke in May 2024, and the route opened to the public.

The infrastructure spans a total length of 8.4 kilometers, the vast majority of which sits directly over the open sea. To navigate the marine environment and allow water and vessel passage, the project incorporates two distinct bridges alongside massive rock embankments:

• Huikun silta (Bridge S1): A 767-meter-long, 9-span continuous steel-concrete composite girder bridge featuring an 18-meter vertical clearance for larger watercraft.
• Riutun silta (Bridge S2): A 737-meter-long, 10-span continuous prestressed concrete girder bridge designed with a 5-meter headroom.

Overcoming Extreme Geotechnical Challenges

Building a multi-kilometer marine highway in northern European conditions is no small feat. The construction area sits upon the Muhos formation, a ancient geological depression filled with tens of meters of soft claystone and shifting sediment layers.