On 12 March 1864, he was promoted to the rank "Leutnant zur See I Klasse", which on 20 May was renamed "Kapitänleutnant". During the Second Schleswig War in 1864 he commanded the armed paddle steamer . He took part in the Battle of Jasmund on 17 March under the command of Eduard von Jachmann. After the war, he served three years attached to the supreme naval command Oberkommando der Marine. There, he served as an adjutant and as a member of the commission for torpedo construction. The Austro-Prussian War took place during this period; since Monts did not have a sea command he saw no action. He served aboard from 1 August 1867 to 27 May 1868. On 20 February 1868 Monts was promoted to "Korvettenkapitän" (lieutenant commander) as part of the section for naval and coastal artillery. Monts became the commander of the Torpedo Command at Wilhelmshaven on 16 July 1870, three days before the outbreak of the Franco-Prussian War. The French Navy attempted to blockade Wilhelmshaven in the early months of the war, but the French ironclads lacked the coal capacity to remain on station long enough to maintain the blockade, and they did not attack the port directly; as a result, Monts saw no action during the war.