Oslo-class

The Oslo-class frigate was developed for the Royal Norwegian Navy as part of a 1960 government rebuilding program. The design was based on the United States Navy Dealey-class destroyer escort. All five vessels in the class were constructed at the Navy Main Yard in Horten, Norway, between 1964 and 1966. The United States provided half of the project funding through the Mutual Defense Assistance Program.

The class featured a modified forward hull with a higher freeboard to accommodate sea conditions in Norwegian waters. While the basic design originated in the United States, several sub-systems were European-built. The vessels underwent multiple modernization programs. During the late 1970s, the ships were fitted with Penguin anti-ship missiles, Sea Sparrow surface-to-air missiles, and Mark 32 torpedo launchers. A second modernization followed in the 1980s. Between 1995 and 1996, the hulls were strengthened, which resulted in an increase in displacement.

The class consisted of five vessels: Oslo, Bergen, Trondheim, Stavanger, and Narvik. These ships entered service between 1966 and 1967, succeeding the River class. They remained in operation until the mid-2000s, when they were replaced by the Fridtjof Nansen class.

The lead ship, HNoMS Oslo, ran aground in January 1994 and sank the following day during a towing operation. HNoMS Stavanger was decommissioned in 1998 and sunk as a target by a submarine-launched torpedo in 2001. HNoMS Bergen was decommissioned in 2005 and used as a target for a bomb test in 2025. HNoMS Trondheim ran aground in 2006; after decommissioning, it served as a target for a Naval Strike Missile test in 2013 and was sunk in 2025. HNoMS Narvik, the final active ship of the class, was decommissioned in 2007 and is preserved as a museum ship at the Royal Norwegian Navy Museum in Horten.