In World War II, the Atlantic pockets were locations along the coasts of the Netherlands, Belgium and France chosen as strongholds by the occupying German forces, to be defended as long as possible against land attack by the Allies.

The locations are known in German as Atlantikfestungen (lit. "Atlantic strongholds") but are known in English as "Atlantic pockets".

Six of the Atlantic pockets were captured by the Allies between June and October 1944. Others were placed under siege. Three surrendered in April 1945, and the remainder in May 1945.

On 19 January 1944 Adolf Hitler declared eleven places along the Atlantic Wall to be fortresses (Festungen), to be held until the last man or the last round, calling them Atlantikfestungen (lit. "Atlantic strongholds").^[1]

The ports were: IJmuiden, the Hoek van Holland, Dunkirk, Boulogne-sur-Mer, Le Havre, Cherbourg, Saint-Malo, Brest, Lorient, Saint-Nazaire and the Gironde estuary.^[1]

In February and March 1944 three more coastal areas were declared to be fortresses: the Channel Islands, Calais and La Rochelle.^[1]

Other fortresses were added after D-Day on 6 June 1944 in further directives of 17 August and 4 September.^{[citation needed]}

As well as concentrating men and matériel to control the surrounding area, the fortresses' purpose was to deny the use of port facilities to the Allies and to secure their continued use by German submarines in the Battle of the Atlantic. In addition, as long as they remained in German hands, they had propaganda value.

In France, six pockets were captured by the Allies between the initial invasion of Normandy in June 1944, and October 1944, and others brought under siege. Three were liberated by French forces in April 1945, while the remainder surrendered after the capitulation of Germany in May 1945.

The Atlantic pockets, with the date any Allied assault began and date the defenders surrendered, are shown below.

• Liberation of France