First, second, third and fourth patrols

The U-boat began her first patrol in the North Sea, keeping to the Norwegian side. She departed Kiel on 24 October 1939 and returned there on 14 November. It was uneventful.

Her second effort started in Kiel on 28 November 1939 but finished in Wilhelmshaven on 3 December.

Patrol number three was the reverse of number two - starting from Wilhelmshaven and finishing in Kiel.

Her fourth patrol continued the start/finish changing; starting in Kiel on 15 January 1940 and was terminated in Wilhelmshaven on the 30th. In between she sank the Sydfold about 120 nautical miles (220 km; 140 mi) east of John o' Groats on the 22nd.

Fifth, sixth, seventh and eighth patrols

U-61's fifth sortie was marked by the sinking of the Sangstad east of Kirkwall (in the Orkney Islands), on 18 February 1940. She had left Wilhelmshaven on 12 February^[4] and along with five other U-boats, took part in Operation Nordmark, a reconnaissance mission for the German capital ships Scharnhorst, Gneisenau and Admiral Hipper (for what proved to be an unsuccessful sortie). It took place in the vicinity of the Orkney and Shetland Islands between 18 and 20 February.^[2]

Her sixth patrol was uneventful, but her seventh foray included a brief stop in the Norwegian port of Bergen, before moving through the gap between the Faroe and Shetland Islands to the waters almost between mainland Scotland and the Western Isles. The return journey was the reverse of the outbound. At 27 days, it was also her longest patrol. She docked in Kiel on 7 May.

U-61's eighth patrol involved moving slightly further south off the western Northern Irish coast. She returned to Bergen on 1 July 1940.

Ninth patrol

For her ninth patrol she departed Bergen on 6 July 1940 and sank Alwaki on the tenth. The ship was hit about 10 nautical miles (19 km; 12 mi) northeast of Cape Wrath (the north-west-most point on the Scottish mainland), by two torpedoes that failed to detonate. But they did create holes large enough to allow the water in. The vessel sank about eleven hours after being hit. The Admiralty investigation into the sinking wrongly concluded that the ship had been sabotaged.

The boat also sank Scottish Minstrel 130 nautical miles (240 km; 150 mi) north-west of the Bloody Foreland (on the Irish mainland), on the 16th.

U-61 returned to Kiel, arriving on the 25th.

Tenth and eleventh patrols

The boat's tenth patrol involved negotiating the Faroer/Shetland gap once again before docking at Lorient in occupied France on 15 September 1940.

Her eleventh and final war patrol was in the other direction. She arrived at the port where she had commenced her war career, Kiel, on 10 October 1940.