Adriatic Campaign of World War II The Adriatic Campaign of World War II was a minor naval campaign fought during World War II between the Greek , Yugoslavian and Italian navies , the " Kriegsmarine " , and the Mediterranean squadrons of the United Kingdom , France , and the Yugoslav Partisan naval forces . Considered a somewhat insignificant part of the naval warfare in World War II , it nonetheless saw interesting developments , given the specificity of the Dalmatian coastline . Prelude — Italian invasion of Albania . On 7 April 1939 , Mussolini ' s troops occupied Albania , overthrew Zog , and annexed the country to the Italian Empire . Naval operations in the Adriatic consisted mostly of transport organisation through the ports of Taranto . Greco - Italian War . The Greco - Italian War lasted from 28 October 1940 to 30 April 1941 and was part of World War II . Italian forces invaded Greece and made limited gains . At the outbreak of hostilities , the Royal Hellenic Navy was composed of the old cruiser , 10 destroyers ( four old " Theria " class , four relatively modern " Dardo " class and two new " Greyhound " class ) , several torpedo boats and six old submarines . Faced with the formidable " Regia Marina " , its role was primarily limited to patrol and convoy escort duties in the Aegean Sea . This was essential both for the completion of the Army ' s mobilization , but also for the overall resupply of the country , the convoy routes being threatened by Italian aircraft and submarines operating from the Dodecanese Islands . Nevertheless , the Greek ships also carried out limited offensive operations against Italian shipping in the Strait of Otranto . The destroyers carried out three bold but fruitless night - time raids ( 14 – 15 November 1940 , 15 – 16 December 1940 and 4 – 5 January 1941 ) . The main successes came from the submarines , which managed to sink some Italian transports . On the Italian side , although the " Regia Marina " suffered severe losses in capital ships from the British Royal Navy during the Taranto raid , Italian cruisers and destroyers continued to operate covering the convoys between Italy and Albania . Also , on 28 November , an Italian squadron bombarded Corfu , while on 18 December and 4 March , Italian task forces shelled Greek coastal positions in Albania . Invasion of Yugoslavia . The Invasion of Yugoslavia ( also known as " Operation 25 " ) began on 6 April 1941 and ended with the unconditional surrender of the Royal Yugoslav Army on 17 April . The invading Axis powers ( Nazi Germany , Fascist Italy and Hungary ) occupied and dismembered the Kingdom of Yugoslavia . When Germany and Italy attacked Yugoslavia on 6 April 1941 , the Yugoslav Royal Navy had available three destroyers , two submarines and 10 MTBs as the most effective units of the fleet . One other destroyer , the " Ljubljana " was in dry - dock at the time of the invasion and she and her anti - aircraft guns were used in defence of the fleet base at Kotor . The remainder of the fleet was useful only for coastal defence and local escort and patrol work . Kotor ( Cattaro ) was close to the Albanian border and the Italo - Greek front there , but Zara ( Zadar ) , an Italian enclave , was to the north - west of the coast and to prevent a bridgehead being established , the destroyer " Beograd " , four of the old torpedo boats and six MTBs were despatched to Šibenik , 80 km to the south of Zara , in preparation for an attack . The attack was to be co - ordinated with the 12th " Jadranska " Infantry Division and two " Odred " ( combined regiments ) of the Royal Yugoslav Army attacking from the Benkovac area , supported by air attacks by the 81st Bomber Group of the Royal Yugoslav Air Force . The Yugoslav forces launched their attack on 9 April , but by 13 April the Italian forces - under the orders of General Vittorio Ambrosio - had counter - attacked and were in Benkovac by 14 April . The naval prong to this attack faltered when " Beograd " was damaged by near misses from Italian aircraft off Šibenik when her starboard engine was put out of action , after which she limped to Kotor , escorted by the remainder of the force , for repair . The maritime patrol float - planes of the Royal Yugoslav Air Force flew reconnaissance and attack missions during the campaign , as well as providing air cover for mine - laying operations off Zara . Some of their successes included an Italian tanker being damaged by a near miss off the Italian coast near Bari , attacks on the Albanian port of Durrës , as well as strikes against Italian re - supply convoys to Albania . On 9 April , one Dornier Do 22 K floatplane notably took on an Italian convoy of 12 steamers with an escort of eight destroyers crossing the Adriatic during the day , attacking single - handed in the face of intense AA fire . Italian occupation and Yugoslav resistance . After the invasion , Italy controlled the entire eastern Adriatic coast through the annexation of much of Dalmatia , the Italian occupation zone of the Independent State of Croatia , and the Italian puppet regimes of the Kingdom of Montenegro ( 1941 – 1944 ) and the Albanian Kingdom ( 1939 – 1943 ) . Naval forces of the Yugoslav Partisans were formed as early as 19 September 1942 , when Partisans in Dalmatia formed their first naval unit made of fishing boats , which gradually evolved into a force able to engage the Italian Navy and Kriegsmarine and conduct complex amphibious operations . This event is considered to be the foundation of the Yugoslav Navy . At its peak during World War II , the Yugoslav Partisans ' Navy commanded nine or 10 armed ships , 30 patrol boats , close to 200 support ships , six coastal batteries , and several Partisan detachments on the islands , around 3 , 000 men . After the Italian capitulation of 8 September 1943 , following the Allied invasion of Italy , the Partisans took most of the coast and all of the islands . On 26 October , the Yugoslav Partisans ' Navy was organized first into four , and later into six Maritime Costal Sectors ( " Pomorsko Obalni Sektor " , POS ) . The task of the naval forces was to secure supremacy at sea , organize defense of coast and islands , and attack enemy sea traffic and forces on the islands and along the coasts . German occupation . As a first move ( Operation Wolkenbruch ) the Germans rushed to occupy the northern Adriatic ports of Trieste , Fiume and Pula , and established the Operational Zone Adriatic Coast OZAK , with its headquarters in Trieste , on 10 September . It comprised the provinces of Udine , Gorizia , Trieste , Pula ( Pola ) , Rijeka ( Fiume ) and Ljubljana ( Lubiana ) . Since an Allied landing in the area was anticipated , OZAK also hosted a substantial German military contingent , the " Befehlshaber Operationszone Adriatisches Küstenland " commanded by " General der Gebirgstruppe " Ludwig Kübler . On 28 September 1944 , these units were redesignated XCVII " Armeekorps " . Soon also German marine units were formed . Royal Navy engagement was also on the rise . German Navy in the Adriatic . " Vize - Admiral " Joachim Lietzmann was Commanding Admiral Adriatic ( " Kommandierender Admiral Adria " ) . Initially , the area of operation ranged from Fiume to Valona , and the area of the Western coast was under the jurisdiction of the German navy for Italy ( " Deutsches Marinekommando Italien " ) . The line of demarcation between the two naval commands and corresponded between the Armed Group F ( Balkans ) and the Armed Group E ( Italy ) as a border between the Italian Social Republic ( RSI ) and the Independent State of Croatia ( NDH ) . Soon on Lietzmann insistence on the area of operation was extended to include the whole of Istria to the mouth of the Tagliamento , and in correspondence to the boundary line between the Italian Social Republic and the area of the Operational Zone Adriatic Coast ( OZAK ) . One of the first operations was Operation Herbstgewitter . This consisted of landing German troops on the islands of Krk , Cres and Lošinj in November 1943 . The Germans used some old ships such as the cruiser and the auxiliary cruiser . During the action , the islands were cleared of partisan forces and " Niobe " with two S - boat s managed to capture a British military mission on the island of Lošinj . Gradually the German navy was built up , mostly with former Italian ships found in an advanced phase of construction in the yards of Fiume and Trieste . The strongest naval unit was the 11th " Sicherungsflotille " . Formed in May 1943 in Triest as the 11 . Küstenschutzflottille , in December 1943 it was designated 11 . Sicherungsflottille . It was employed in protecting marine communications in the Adriatic , mostly from partisan naval attacks . On 1 March 1944 , the Flotilla was extended and re - designated the 11 . Sicherungsdivision . Occupation of Dalmatia . Until the end of 1943 , the German forces were advancing into Dalmatia after capitulation of Italy . In the summer of 1944 , the Allies undertook a major evacuation of civilian population from Dalmatia fleeing the German occupation , and moved them to the El Shatt refugee camp in Egypt . Vis island . By 1944 , only Vis island remained unoccupied and divisions task become its defense against later cancelled German invasion ( Operation FREISCHÜTZ ) . The island was about long and wide , with a mainly hilly perimeter , with a plain in the centre covered with vines , part of which has been removed to make way for an airstrip about long , from which four Spitfire s of the Balkan Air Force were operating . At the west end of the island was the Port of Komiža , while at the other end was the Port of Vis , these were connected by the only good road running across the plain . Vis was organized as a great stronghold , held until the end of World War II . In 1944 , Tito ' s headquarters moved there and British forces with over 1 , 000 troops was also included in the defence of Vis . The British forces , already on the island , were called Land Forces Adriatic , and were under the command of Brigadier George Daly , and consisted of the No . 40 ( Royal Marine ) Commando and No . 43 ( Royal Marine ) Commando of the 2nd Special Service Brigade , the Highland Light Infantry ( part of the 51st Highland Infantry Division ) and other support troops . Operating from the two ports were several Royal Navy craft , Marshal Tito ' s forces numbered about 2 , 000 . Vis was functioning as the political and military center of the liberated territories until the liberation of Belgrade in late 1944 . A remarkable figure was the Canadian captain Thomas G . Fuller , son of the Canadian Chief Dominion Architect Thomas William Fuller , who in 1944 took command of the 61st MGB flotilla . Operating from the island of Vis he supplied the partisans by pirating German supply ships . He managed to sink or capture 13 German supply boats , was involved in 105 fire fights and another 30 operations where there was no gunfire . Characteristically for the Yugoslav operations theatre , Fuller attributed a good part of his success to the blood - curling threats uttered by the Yugoslav partisan who manned the MGB ' s loud hailer : a 400 ton schooner was captured with its whole cargo and whose crew gave up without a struggle because of the explanation of what would be done to them personally , with knives , if they disobeyed . Liberation of Dalmatia . British naval forces in the Middle East operating in the Adriatic Sea were under the command of the Flag Officer Taranto and Adriatic & Liaison with the Italians ( F . O . T . A . L . I ) . All the naval forces were controlled from Taranto and operated in close coordination with the Coastal attack operations conducted by the BAF . The Yugoslavs used the units in the British navy to transport materials and men , but especially to make landings on the islands of Dalmatia to liberate them from German occupation . During the Vis period , Partisans carried out several seaborne landings on Dalmatian islands with help of Royal Navy and Commandos : The French Navy was involved as well in the first half of 1944 , with the 10th Division of Light Cruisers made up of three " Fantansque " - class destroyer s ( " Le Fantasque " , " Le Terrible " , " Le Malin " ) making high speed sweeps in the Adriatic , destroying German convoys . In the second half of 1944 the Royal Navy sent a destroyer flotilla in the Adriatic . The biggest engagement happened on 1 November , when two " Hunt " - class destroyer s and were patrolling the coastal shipping routes south of Lussino in the Adriatic . That evening , two enemy corvettes were sighted ; " UJ - 202 " and " UJ - 208 " . The two destroyers opened fire at a range of . In less than 10 minutes , the enemy ships were reduced to mere scrap , the two British ships were circling the enemy and pouring out a devastating fire of pom - pom and small calibre gunfire . When the first corvette was sunk " Avon Vale " closed to rescue the Germans while " Wheatland " continued to shoot up the second corvette which eventually blew up . Ten minutes later , the British came under fire from the German " Torpedoboot Ausland " destroyer " TA - 20 " ( ex - Italian destroyer Audace ) which suddenly appeared on the scene . When the two British ships directed their fire at her and the enemy destroyer was sunk . But while the Adriatic campaign continued to the end of the war , the Hunts did not again engage large German warships , although the German Navy was constantly launching and commissioning light destroyer types from the yards of Trieste and Fiume . Moreover , on 14 December , struck a mine around the island of Škrda and it was the last British destroyer lost in World War II . To prevent entrance to the North Adriatic in the last two years of World War II , Germany spread thousands of mines and blocked all ports and canals . Many underwater mine fields were situated in the open sea . Mine sweeping was executed by British ships equipped with special mine - sweeping technology . On 5 May 1945 , the " Shakespeare " - class trawler hit a mine while it was sweeping the sea in front of Novigrad . Planned allied landings . The Allies , first under French initiative of the general Maxime Weygand planned landings in the Thessaloniki area . Although discarded by the British , later the landing option became most advocated by Winston Churchill . The so - called Ljubljana gap strategy proved ultimately to be little more than a bluff owing to American refusal and skepticism upon the whole operation . nevertheless , the British command planned several landing operations in Dalmatia and Istria codenamed ARMPIT and a more ambitious plan GELIGNITE . Facing American opposition the British made last attempts were marked by sending an air force called FAIRFAX in Zadar area , and an artillery attachment called FLOYD FORCE also in Dalmatia , but due to Yugoslav obstruction such attempts ceased . Nevertheless , the bluff worked since Hitler eventually awaited an allied landing in the northern Adriatic , and diverted important resources in the area . Instead of landings the allied agreed to provide Tito land units with aerial and logistical support by setting up the Balkan Air Force . The biggest British - led combined operation in the eastern Adriatic codenamed Operation Antagonise in December 1944 was intended to capture the island of Lošinj , where the Germans kept E - boats and ( possibly ) midget submarines . It was only partially executed since the partisan Navy Commander in Chief , Josip Černi , refused to give his troops for the landing operation . Instead , a group of destroyer s and MTB s shelled the German gun positions and 36 South African Air Force Bristol Beaufighter s attacked the naval base installations with RP - 3 Rocket Projectiles As the attacks proved ineffective in stopping German activities they were repeated also in the first months of 1945 . Final naval operations . By the end of October 1944 , the Germans still had five destroyers ( " TA20 " , " TA40 " , " TA41 " , " TA44 " , and " TA 45 " ) three corvettes ( " UJ205 " , " UJ206 " , and " TA48 " ) . On 1 January 1945 , there were four German destroyers operative in the northern Adriatic ( " TA40 " , " TA41 " , " TA44 " , and " TA 45 " ) three U - Boot " Jäger " corvettes ( " UJ205 " , " UJ206 " , and " TA48 " ) . even as late as 1 April TA43 , " TA 45 " and " UJ206 " were in commission and available to fight . Allied aircraft sank four in port ( at Fiume and Trieste ) in March and April , British MTB torpedoed " TA 45 " in April . The very last operations of the German navy involved the evacuation of troops and personnel from Istria and Trieste before the advancing Yugoslavs that took place in May 1945 . An estimated enemy force of 4 , 000 was landing from 26 ships of all types at the mouth of the Tagliamento River at Lignano Sabbiadoro . The area is a huge sand spit running out into a big lagoon , and at its southern end the Tagliamento River enters the sea . The Germans had evacuated Trieste to escape the Yugoslav Army . The Germans were protected by naval craft holding off three British MTBs , which could not get in close enough to use their guns effectively . There were about 6 , 000 of them and their equipment included E - boats , LSTs , a small hospital ship , all types of transport , and a variety of weapons . The 21st Battalion of the New Zealand 2nd Division was outnumbered by 20 to one , but at the end the Germans surrendered on 4 May 1945 . Others had already surrendered to the British troops on German ships which arrived from Istria to Ancona on 2 May . British sources wrote there were about 30 boats , but no exact record is mentioned .