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.