In April 1918 Keyes planned and led the famous raids on the German submarine pens in the Belgian ports of Zeebrugge and Ostend. He was advanced to Commander of the Royal Victorian Order on 30 March 1918 and promoted Knight Commander of the Order of the Bath on 24 April 1918. He was then advanced to Knight Commander of the Royal Victorian Order on 10 December 1918 and made a baronet on 29 December 1919. In March 1919 he was appointed (Acting) Vice-Admiral in command of the Battle Cruiser Force until it was disbanded in April 1919.