At the time of separation, the Royal Dano-Norwegian Navy was in a poor state and Norway was left with the lesser share.

All officers of Danish birth were ordered to return to Denmark and the first commander of the Norwegian navy became Captain Thomas Fasting.

In 1900, just five years prior to the separation from Sweden, the navy, which was maintained for coastal defence, consisted of: two British-built coastal defence ships (HNoMS Harald Haarfagre and HNoMS Tordenskjold – each armored and displacing about 3,500 tons), four ironclad monitors, three unarmored gun vessels, twelve gunboats, sixteen small (sixty ton) gunboats, and a flotilla of twenty-seven torpedo boats.

The neutrality was sorely tested – the nation's merchant fleet suffered heavy casualties to German U-boats and commerce raiders.

[7] World War II began for the Royal Norwegian Navy on April 8, 1940, when the German torpedo boat Albatross attacked the guard ship Pol III.

The German invasion fleet – believing Blücher had struck a mine – retreated south and called for air strikes on the fortress.

On June 7, 1940, thirteen vessels, five aircraft and 500 men from the Royal Norwegian Navy followed the King to the United Kingdom and continued the fight from bases there until the war ended.

"Ubåtvåpenet" maintain six Ula-class submarines: Note: These ships are generally considered destroyers by their officers and other navies due to their size and role.

[11] Helge Ingstad (F313) was decommissioned and sold for scrap after a collision with an oil tanker in November 2018 severely damaged the ship.

In February 2017 the German manufacturer Thyssen Krupp was selected to deliver four new submarines, of the Type 212CD submarine-class design, starting in the latter 2020s [19] to replace the Ula-class boats.

A firm build contract with Thyssen Krupp was anticipated in the first half of 2020 as part of a joint program under which Norway will procure four submarines and Germany two.

In March 2021 it was indicated that an agreement had been reached between Norway and Germany to initiate the acquisition program, pending approval by the Bundestag.

[25] The Coast Guard is replacing its existing Nordkapp-class vessels with significantly larger ice-capable ships, each displacing just under 10,000 tonnes.

[29][30] The second ship of the class, KV Bjørnøya, was transferred to Norway for her final fit out at the Vard Langsten yard in February/March 2022[31][32][33] and was delivered in November 2023.

To be procured under Project P6380, the vessels are to have a top speed of 45 knots, stay at sea for up to a week and hold a crew of up to six personnel along with a coastal ranger platoon, its equipment or, alternatively, a UAV under 150kg for day/night operations.