AtNorth is adding a new data center building to its FIN04 campus in Myllykoski, Kouvola, Finland.

The data center company signed on YIT this week as the main contractor to construct a new facility - FIN04A1 - at the campus, including mechanical, electrical, and plumbing works.

YIT was also selected as the contractor for a second building on the campus in July 2026.

The value of the agreement has not been shared, nor have timelines for construction.

"We are pleased to continue and deepen our collaboration with atNorth. The FIN04 campus in Myllykoski is one of the most significant data center developments in Finland, and it is great to be part of its next phase. As Finland’s leading data center builder, YIT has strong expertise in delivering technically demanding projects and meeting the high quality, safety, and security of supply requirements of the industry. We look forward to supporting atNorth in the continued development of the FIN04 campus and its future opportunities in Myllykoski,” said Aleksi Laine, EVP, Infrastructure segment at YIT.

AtNorth filed to expand the campus back in February 2026, requesting a permit to add three data center buildings in Kouvola, which is still under development.

Kouvola is the administrative capital of Kymenlaakso, located some 135km (83.8 miles) northeast of Helsinki.

Plans for FIN04 were first announced in late 2023. At the time, the company said the 23-hectare site would open with 60MW with potential to reach "several hundred megawatts" when fully built. The company now lists the site as offering up to 430MW of capacity across 45 hectares, with a path to “several hundred additional megawatts.”

In March 2026, the company noted that two of the buildings were approaching completion, and atNorth was beginning hiring for the operation of the sites.

YIT is a construction company in Finland that has been operating for more than 110 years. It does infrastructure, residential, and commercial construction work.