The Germans attacked Norway with an amphibious force. The first naval action of the campaign was a chance encounter between the British destroyer Glowworm and German destroyers and the cruiser Hipper. The Glowworm rammed the Hipper tearing a hole in its side before being destroyed. The pocket battleship Lutzow (Deutchalnd) and the cruiser Blucher were sent through the fifty mile Oslo Fjord. At the point were it narrows to 500 yard a series the Blucher was destroyed by Norwegian coastal guns and torpedoes. The Lutzow took three 11 inch shells but made it through.

The British responded with an attack on German shipping in Navirick harbor on the morning of April 10, 1940. Five British destroyers the Hardy, Hotspur, Havock, Hostile and Hunter entered the harbor and quickly sank the Wilhelm Heidkamp and the Anton Schmidt. they also severely damaged the Hans Luwedemann, Dither von Roeder and Herman Kuenne. AS they withdrew the Hardy and the Hunterh were sunk while leaving.

On June 8 the HMS Glorious which had arrived from the Mediterranean was sunk by the German pocket battleships Scharnhorst and Gneisenau. This was the only time that battleships have ever sunk an aircraft carrier. The fact that the Glorious had no planes aloft,nor was the crows nest manned, made this outcome possible.