"T11" was ordered on 29 June 1936 from DeSchiMAG, laid down at their Bremen shipyard on 1 July 1938 as yard number 938, launched on 1 March 1939 and commissioned on 24 May 1940. The boat was working up until July when she was transferred to the Skaggerak for convoy escort duties. On 18 September, "T11" was slightly damaged by bomb splinters when the Royal Air Force bombed Cherbourg, France. Several of her crew were wounded during the attack. She returned to Germany in December and was decommissioned for repairs that lasted until June 1941. The boat was recommissioned and assigned to the Baltic Sea where she escorted, together with her sister ships and , the light cruisers and as they supported German forces invading the Estonian islands of Ösel, Dagö and Muhu (Operation Beowulf) in mid-September. "T11" and her sisters , , "T7", and "T8" were among the escorts for the Baltic Fleet, a temporary formation built around the battleship , as it sortied into the Sea of Åland on 23–29 September, to forestall any attempt by the Soviet Red Banner Baltic Fleet to breakout from the Gulf of Finland.