The 'Tallinn Defensive Operation' was the unsuccessful Soviet undertaking to hold Tallinn, the largest city of Estonia and the Baltic Fleet’s main operational base on the southern side of the Gulf of Finland (5/28 August 1941).

On 22 July the German forces of Generalfeldmarschall Wilhelm Ritter von Leeb’s Heeresgruppe 'Mitte', advancing through the Soviet-occupied Baltic states toward Leningrad, had broken through the Soviets' defences along the line linking Pärnu, Tartu and Lake Peipus, and now readied themselves to reach and take Tallinn: this lies on the north-west corner of the mainland, and in German hands would not only prevent the movement of Soviet ships, both naval and mercantile into and out of the Gulf of Finland, but also provide the Germans with very useful port facilities for the logistical furtherance of their assault toward Leningrad.

On 5 August, elements of Generaloberst Georg von Küchler’s 18^th Army reached the distant approaches to Tallinn, and two days later reached the coast of the Gulf of Finland in the area of Kunda, to the east of Tallinn. As a result, the two corps of General Major Ilya M. Lyubovtsev’s 8^th Army, part of General Leytenant Markian M. Popov’s North Front, to which it had been transferred from General Major Piotr P. Sobennikov’s North-West Front, were cut in two: General Major Ivan F. Nikolayev’s X Corps began to retreat westward toward Tallinn and General Major Mikhail S. Shumilov’s XI Corps eastward toward Narva.

Under the command of Popov, the Soviet strength in the Tallinn area totalled some 20,000 men: units of the X Corps and marines numbered about 14,000 men supported by one tank company operating between 11 and 13 T-26 light tanks, one regiment Estonian and Latvian workers, supported by ships, coastal artillery and aircraft of Vitse Admiral Vladimir F. Tributs’s Baltic Fleet.

Tallinn had not been prepared in advance for defence against a land assault, although some underground structures, built before World War I by the Russian imperial government, remained in the city. Construction of three defensive lines around Tallinn began on 17 July under the supervision of the Baltic Fleet’s engineering department, and troops, naval personnel and the civil population of Tallinn were involved in the construction work. The main defensive zone was built at a distance of between 5.6 and 7.5 miles (9 and 12 km) from the city, and included 24.25 miles (39 km) of anti-tank ditches, 10,000 concrete, 5,000 metal and 6,000 wooden posts, some 37 miles (60 km) of barbed wire entanglements, forested area and both light artillery and machine gun bunkers. Work on the defences was was not completed, however.

Against the Soviet troops defending Tallinn, the Germans concentrated four infantry divisions with as many as 60,000 men, reinforced with artillery, tanks and aircraft.

On 5 August, Tributs ordered the establishment of a defence headquarters of the main base under the command of General Major Gavrili S. Zashikhin, the commander of the Baltic Fleet’s air defence organisation.

Despite the German forces' significant superiority in men and weapons, the defence had slowed the German advance by 10 August, but the Germans maintained their pressure and by 19 August had reached the forward edge of Tallinn’s defences. One day later, after bringing forward fresh forces, the Germans resumed the offensive, delivering their main blow from the east along the coast, where the defenders occupied positions weaker than those of other parts of the defensive arrangement. On 25 August, Soviet troops withdrew to the main line of defence in the suburbs of Tallinn, and from their positions against this defensive line the German artillery was able to engage all targets in the city and the naval base. One day later, the Soviet supreme command decided to order the relocation of the Baltic Fleet and Tallinn’s garrison to Leningrad and Kronstadt, the latter being the island naval base off Leningrad.

Even before the start of this redeployment, and thus within the context of the defensive battle for Tallinn, the Baltic Fleet managed to remove almost all of the arsenal, part of the shipyard, about 15,000 tons of technical equipment, about 17,000 women and children, and about 9,000 wounded. This evacuation was achieved under the supervision of a special evacuation commission under the leadership of the Baltic Fleet’s chief of rear services, General Major Mitrofan I. Moskalenko.

On 27 August, Tributs was ordered to evacuate to Kronstadt, and on this day the Germans into Tallinn, where stubborn street battles began. The evacuation began on 28 August. With only very limited capability to survive the continuous German air attacks, ands operating in heavily mined waters, the Baltic Fleet succeeded between 28 and 30 August in moving more than 100 warships and naval craft, together with 67 transport and support vessels, freight and 20,500 troops, eastward to Kronstadt.

Tallinn fell to the Germans after the evacuation, and the Germans counted 11,432 men taken prisoner and the capture of 97 pieces of artillery, 52 anti-tank guns, 144 anti-aircraft guns, 91 armoured vehicles, two armoured trains, 304 machine guns, 4,000 mines, 3,500 torpedoes and more than 1,000 bombs.

Although the defence of Tallinn had resulted in the diversion of substantial German forces, it did not have a significant impact on the course of hostilities in the Leningrad strategic direction. The Germans' rapid advance toward Leningrad paralysed the Baltic Fleet’s capability to achieve any significant influence the course of the war. For the bulk of the Eastern Front campaign, therefore, the Baltic Fleet remained bottled in the ports at the eastern end of the Gulf of Finland, trapped by huge minefields laid by the German and Finns.