During the final months of World War I, O-9 operated on coastal patrol and protected the Atlantic coast from U-boats.

During the early months of World War I, Kars was a key military objective for the Ottoman army.

Vanity saw service in the last months of World War I, which ended with the armistice with Germany on 11 November 1918.

He was involved as a soldier in the last months of World War I, fighting on the Western Front in Belgium.

The northern campaign lasted from the final months of World War I in 1918 through to 1919.

During the early months of World War I, it was soon discovered that the Pickelhaube did not measure up to the demanding conditions of trench warfare.

Commissioning during the final months of World War I, O-15 saw brief war time service, on patrol along the Atlantic coast.

In the last few months of World War I, Whiddy became the site of a US naval air station.

Commissioning during the final months of World War I, O-16 had little wartime duty.

In the first months of World War I, heavy fighting between Russians and Austrians took place here.