The Type VIIC was the workhorse of the German U-boat force, with 568 commissioned from 1940 to 1945. The first VIIC boat commissioned was the U-69 in 1940. The Type VIIC was an effective fighting machine and was seen almost everywhere U-boats operated, although its range of only 8,500 nautical miles was not as great as that of the larger Type IX (11,000 nautical miles), severely limiting the time it could spend in the far reaches of the western and southern Atlantic without refueling from a tender or U-boat tanker. The VIIC came into service toward the end of the "First Happy Time" near the beginning of the war and was still the most numerous type in service when Allied anti-submarine efforts finally defeated the U-boat campaign in late 1943 and 1944.

Type VIIC differed from the VIIB only in the addition of an active sonar and a few minor mechanical improvements, making it 2 feet longer and 8 tons heavier. Speed and range were essentially the same. Many of these boats were fitted with snorkels in 1944 and 1945.