Germany lost 630 U-boats in operations during World War II, using the commonly cited count of boats lost at sea. The figure captures the catastrophic attrition suffered by the Kriegsmarine’s submarine force.
The 630 figure is associated with losses during wartime operations rather than every submarine that was eventually removed from service. One widely cited breakdown records 603 lost through enemy action, seven through accidents, and 20 from unknown causes.
The total can vary depending on what a historian includes. Additional German U-boats were destroyed in port, scuttled by their crews at the end of the war, surrendered, captured, or lost through other non-operational circumstances. That is why some references give totals above 700 or even close to 800.
Germany began the war with a relatively small submarine fleet and used wolf-pack tactics to attack Allied convoys. Early successes were followed by increasingly effective radar, sonar, codebreaking, escort carriers, and long-range patrol aircraft. By 1943, U-boat losses had become so severe that Germany’s Atlantic campaign could no longer achieve its strategic goal.