The offensive was hampered by the quick German ground advance and the retreat of Soviet naval vessels from the main Baltic harbors.

At the beginning of the conflict the Soviet Navy operated a formidable force on paper, consisting of 75 submarines.

However, only 35 submarines were operational: 15 of them were located in the Latvian port of Liepāja and were ordered to retreat to Tallinn due to the rapid German ground advance.

[7] On 6 August, Soviet submarine S-6 went missing: wreck discovered in Swedish waters off Öland in 2012, loss due to mine.

[11] On 28 September, Soviet submarine ShCh-319 was possibly the boat responsible for a failed torpedo attack reported on German cruiser Leipzig off Sworbe.

[16] On 16 October, Soviet submarine ShCh-323 torpedoed and sunk German merchant "Baltenland" (3724 GRT) off the Swedish coast.

Due to the German defensive and offensive minelaying and subsequent British aerial mining, the success scored can't be confirmed.

[27] Another problem for Soviet submarines was operating in shallow waters, making little room for depth maneuvers in addition to the risk of mines and air attack.