Norway has announced plans to acquire British-built warships tailored for anti-submarine operations, marking the country’s most substantial defense investment to date.

The government has chosen the United Kingdom as its key partner for procuring new Type-26 frigates, developed primarily by BAE Systems. Valued at $13.5 billion, the agreement covers the delivery of at least five vessels, which will be constructed at BAE’s Glasgow facilities.

This contract is considered a major success for the U.K. defense sector, following a nine-month competition in which Norway evaluated offers from France, Germany, and the United States. “It was not an easy decision—each of the four bidders presented strong, competitive proposals. They are all close allies, and our cooperation on security and defense will continue robustly with each of them,” said Prime Minister Jonas Gahr Støre.

The first frigates are expected to arrive in 2030, with Oslo intending to keep them in service for decades. They are also expected to operate alongside anti-submarine helicopters, though Norway has yet to finalize which model will be selected.

A distinctive feature of the arrangement is that Norway’s ships will closely match those of the Royal Navy in design and capability. Defense Minister Tore O. Sandvik highlighted that aligning specifications will maximize interoperability, reduce costs, and simplify maintenance. He also noted the potential for shared training and even interchangeable crews between the two navies under the strategic partnership.

Key systems on the Type-26 include a medium-caliber gun, MBDA’s Sea Ceptor air-defense missiles, and BAE’s Artisan 3D radar, designed to track small, fast-moving threats, according to the manufacturer. Currently, eight Type-26 frigates are in production for the Royal Navy to replace its Type-23 fleet, while Australia and Canada have also placed orders for similar versions.