The Otranto Barrage was an Allied naval blockade of the Strait of Otranto between Brindisi in Italy and Corfu on the Greek side of the Adriatic Sea in the First World War. The operation consisted of over 200 vessels at the height of the blockade. The blockade was intended to prevent the Austro-Hungarian Navy from escaping into the Mediterranean and threatening Allied operations there. The blockade was effective in preventing surface ships from escaping the Adriatic, but it had little or no effect on the submarines based at Cattaro.

The Austro-Hungarian Navy or Imperial and Royal War Navy was the naval force of Austria-Hungary. Ships of the Austro-Hungarian Navy were designated SMS, for Seiner Majestät Schiff. The k.u.k. Kriegsmarine came into being after the formation of Austria-Hungary in 1867, and ceased to exist in 1918 upon the Empire's defeat and subsequent collapse at the end of World War I.