Guide to Finland’s New Hailuoto Bridge and Causeway

Bridging the Gulf: How the New Hailuoto Fixed Connection Transformed a Unique Finnish Island

For decades, reaching Hailuoto—the largest island in the interior of the Gulf of Bothnia and a crown jewel of Northern Ostrobothnia, Finland—demanded patience. Separated from the mainland by a roughly seven-kilometer stretch of icy, windswept sea, residents, visitors, and commercial freighters relied entirely on a public road ferry. In the depths of winter, an ice road would occasionally form, offering a thrilling but weather-dependent shortcut.

The opening of the Hailuoto fixed road connection—featuring its iconic twin bridges—marked the end of an era, replacing the historic ferry service that had run since 1968. This monumental engineering feat permanently changed the rhythm of life on the island.

Anatomy of an Engineering Marvel

The fixed connection is an 8.4-kilometer (5.2-mile) corridor linking Riutunkari on the Oulu mainland to Huikku on Hailuoto. Rather than a single continuous bridge, the project is a hybrid infrastructure marvel consisting of roughly 6.9 kilometers of robust rock embankments interspersed with two major bridges:

• The Huikku Bridge: A continuous steel-concrete composite girder bridge measuring 767 meters in length with an 18-meter clearance, allowing boat traffic to pass underneath. Its frame utilizes weather-resistant steel designed to withstand harsh northern marine environments.
• The Riuttu Bridge: A 737-meter-long continuous prestressed concrete girder bridge with a 5-meter headroom.

Constructed using an alliance model partnering the Finnish Transport Infrastructure Agency with builders like GRK Suomi and lead designers like AINS Group and AFRY, the project tackled fierce geotechnical hurdles. The seabed rests on the complex Muhos formation—featuring deep, soft claystone layers that required massive, deeply driven steel and concrete piling to anchor the structures for a projected 100-year service life.

Why the Change?

While the 25-minute ferry ride offered a romantic, slow-paced introduction to Hailuoto’s sweeping sandy beaches and pine forests, it came with mounting structural and financial hurdles.

The aging ferry fleet required multi-million-euro renewals, and annual operating costs hovered around EUR 6 to 7 million. Furthermore, the fixed timetable and lack of overnight sailings isolated the island’s roughly 1,000 residents, making daily commuting, emergency responses, and logistics complicated.

The new fixed link slashed travel time across the water to roughly eight minutes, seamlessly integrating Hailuoto into the greater Oulu region’s commuter and economic zone.

A New Chapter for an Ancient Island

Hailuoto is a geological wonder—a young island still rising from the sea due to post-glacial land uplift. For generations, its physical isolation preserved its distinct cultural character, rich birdlife, and pristine natural habitats.