The Soviets, with a little help from their Scandinavian neighbours, made up their mind for them in the Baltic. On 27 September 1944, the neutral Swedish government announced that its Baltic harbours were no longer open to German shipping of any kind and a couple of days later the Finns led the first three of fifteen Soviet submarines from the Gulf of Finland past the defence posts on Hangö and Abo out into the Baltic beyond where they could begin operating off the Latvian, Lithuanian and Polish coastlines. On 29 September the Soviets reinforced the message that the Germans were unwelcome in these waters by landing troops on Moon Island. A German retreat to Ösel (Hiiumaa) swiftly followed. Dagö was taken next on 3 October and a further withdrawal from Ösel to the Sworbe Peninsula on the island of Saaremaa followed later in the month. In an effort to arrest this breakthrough into the Baltic, the Germans employed their heavy cruisers, Lützow and Prinz Eugen, three destroyers and four torpedo boats against the new Soviet positions on the coast between Libau (Liepāja) and Memel (Klaipẻda) in the second week of the month and then used some of these vessels to bombard the enemy troops on the Sworbe Peninsula on 22–24 October. Few could have doubted that these were merely delaying tactics by the Germans for the war in the Baltic States had moved inexorably against them. Much of Estonia had gone, entry into the Gulf of Riga had been secured and Latvia’s ‘liberation’ was at most only weeks away. As part of these measures, the final attack on the Sworbe Peninsula was made by the Soviet 8th Army on 18 November, with fire support coming from three gunboats and eleven armoured cutters gathered off the east coast. Despite putting up some naval resistance over the next few days, the game was essentially up for the Germans and the arrival of the pocket battleship Admiral Scheer, along with a task force of two destroyers and six torpedo boats, was merely designed to slow the advance of the 8th Army and cover the latest evacuation that took place during the night of 23–24 November.
In the Baltic in the new year , the writing had been on the wall for Dönitz and the Kriegsmarine from mid-January onwards when the Soviets had opened their three-front drive on East Prussia from Pultusk in the south and Gumbinnen (Gusev) and Tilsit (Sovetsk) in the north. This move had prompted the Germans to evacuate their XXVIII Corps from Memel (Klaipẻda) across the ice to the Kurische Nehrung over a four-day period (24–28 January) and to withdraw the injured, sick and refugees by boat from Memel before either Soviet submarines or the men of the 1st Baltic Front from Tilsit could prevent them from doing so. Unless the Soviets were stopped in their tracks, all hope for Germany would be lost. Staring defeat in the face, the Germans responded by organising a series of counter-attacks in an effort to restore land communications between Königsberg (Kaliningrad) and its port of Pillau (Baltiysk). Dönitz was obliged to support these efforts from offshore and did so by deploying the heavy cruisers Admiral Scheer, Lützow and Prinz Eugen, a couple of gun carriers, together with a handful of destroyers and torpedo boats to provide as much artillery bombardment as possible against the advancing Soviet troops around Königsberg. It was never going to be anything more than a mere delaying tactic, but it was vital if the Germans were to succeed in organising a massive evacuation from the Baltic States and East Prussia to the western ports of Germany. Generaladmiral Oskar Kummetz and the Marineoberkommando Ost/Ostsee (German Naval High Command East) were given overall responsibility for planning and delivering what was to become the largest evacuation exercise ever attempted. Faced with the enormity of this problem, Kummetz and his team needed to utilise as many ships of a decent size as they could lay their hands on. This vital task was entrusted to Konteradmiral Conrad Engelhardt, the Wehrmacht’s naval transport commander and he became responsible for procuring the evacuation vessels. Fourteen large passenger ships, a dozen of which were over 13,000 tons, twenty-two freighters of over 5,000 tons, unknown numbers of smaller vessels, as well as auxiliary warships and escort vessels were all pressed into service over the course of the next few months as the scale of the military crisis became increasingly more evident as time went by. Organising convoys was difficult enough at the best of times, but under real pressure from an advancing army the logistical complexities became even more horrendous than normal. In order for their scheduling system to work efficiently, Kummetz and Engelhardt needed more than organisational discipline and great stoicism. They also needed a monumental slice of luck – not least because the Soviet submarine fleet had every intention of disrupting the evacuation as and when it could. Lacking the cutting-edge of a suitable number of destroyers and other anti-submarine vessels until the latter half of February, the Germans were left with making the best of the flotillas of minesweepers, patrol boats, submarine chasers, heavy and light gunboats, gun ferry barges, naval fishing cutters, naval ferry barges, converted trawlers and many small fishery vessels that were available to them in Baltic waters.
A start was made to the evacuation on 25 January when three passenger ships sailed from Pillau with the first batch of 7,100 refugees. Within three days some 62,000 people had been moved westwards away from the Red Army, but merely boarding the boats that ranged alongside the dockyards was no guarantee that safety was assured. Apart from the Soviet submarines that initially concentrated on the sea route from Courland, and their larger boats which congregated in the area of the Stolpe Bank and off the Danish island of Bornholm, the greatest threat to these evacuees came from the RAF dropping a total of 3,220 air mines in the western Baltic and as far east as the Pomeranian coast in the first three months of 1945. These mines were to reap a rich harvest of shipping victims. In all some 137,764 tons of German shipping was sunk and 71,224 tons was damaged in this mining blitz. Although the mines were completely undiscriminating – taking out hospital ships as well as transports, destroyers and minesweepers – it could have been much worse had the Soviet Air Force been actively involved. Instead they were largely deployed on land operations and so Kummetz and Engelhardt were given an extended opportunity to continue evacuating large numbers of Germans from the dwindling Eastern Front. Each of the large passenger ships involved in these operations could take 5–9,000 passengers on board and the freighters could hold up to 5,000 at a time. It was crucial, therefore, that these ships should be pressed into making as many return journeys as possible to extricate the largest number of evacuees from the Baltic States. Unfortunately, not all of these ships could be escorted to and fro and occasionally a passenger vessel or a freighter sailing independently was discovered by a submarine and sunk with impunity. In this way the third largest passenger ship used in the evacuation operation, Wilhelm Gustloff, a liner of 25,484 tons with 10,582 people on board, was sunk off the Polish coast on 30 January by S-13 with the loss of over 9,330 victims making it the largest maritime disaster of all time. S-13, loitering with intent off the Stolpe Bank, also managed to evade two escorts in order to sink the tenth largest passenger ship General Steuben on 10 February with the loss of another 3,608 lives.
Complications set in with the Soviet advance on Eastern Pomerania in late February since some of the ships and naval ferry barges as well as the Gun Carrier Flotilla being used in the East Prussian and Courland evacuations were now needed off the Pomeranian coast to take more refugees from the port of Kolberg (Kolobrzeg), or to support the heavy cruiser Admiral Scheer, three destroyers and a torpedo boat in defending the bridgehead at Wollin (Wolin). Desperate measures resulted in another 75,000 refugees, soldiers and wounded being withdrawn from this front by 18 March. They had not even finished this tricky assignment when the Germans were forced to respond to yet another setback – this time the opening of a Soviet drive from Marienwerder (Kwidzyn) to Gotenhafen (Gdynia) and Danzig (Gdańsk). Once again, naval firepower was needed to keep the Soviet 2nd White Russian Front from breaking through before refugees could be evacuated. On 10 March the heavy cruiser Prinz Eugen was pressed into service and five days later the obsolete battleship Schlesien along with three heavy auxiliary gunboats and a gunnery training vessel also battered the Soviet positions from offshore. After Schlesien ran out of shells, the heavy cruiser Lützow and two destroyers replaced her on 23 March and the light cruiser Leipzig was added to the bombardment force. Evacuations of refugees began from the naval base at Gotenhafen and the ports of Danzig and Hela (Hel) as the Red Army moved ever closer to the Gulf of Danzig, but on this occasion two divisions of the Soviet Naval Air Force were also involved in carrying out over 2,000 sorties against the operation. In an effort to neutralise the torpedo-bombers over these ports, Kummetz ordered a group of destroyers, torpedo boats and other warships to stand by and provide an effective curtain of A.A. fire to cover the transports as they took on their passengers and left port with them. Although Soviet aircraft still managed to sink five transports, two minesweepers and a submarine-chaser, many German ships were still able to enter and leave these three ports unscathed. Soviet mine barrages did claim a couple of torpedo boats and a U-boat (U367) and their submarines did sink a freighter, a patrol boat and a tug while on passage, but the vast majority of craft laden with refugees made safe landfall in other German ports further to the west. A day before Gotenhafen fell on 28 March the battleship Gneisenau – a constant and frustrating nemesis of the Allies throughout the war – made an undistinguished exit when she was finally sunk as a blockship. At that late stage this sacrificial act served very little useful purpose. Once Danzig was captured on 30 March, Hela became the operational centre for the evacuation. It became a kind of halfway house for refugees from those ports around the Gulf that hadn’t been occupied by Soviet troops and a total of 264,887 evacuees found their way to the port in a multitude of small boats and naval ferry barges in April alone. Adding to the armada of vessels making for Hela were retreating troops and other refugees from collapsed fronts, such as the Oxhöfter Kämpe bridgehead and Engelhardt’s passenger ships which by now had plenty of practice at being used as evacuation transports. Such was the scale of the operation that by 10 April 157,270 wounded servicemen had left Hela for the west. Increasingly, however, the casualties of this evacuation would grow as Soviet air and sea forces devoted more time and resources to attacking this traffic.