She saw extensive action during the Arctic and North Atlantic convoys of the Second World War. These included Convoy ONS 5 in May 1943, regarded as the turning point of the Battle of the Atlantic. At 03:00 on 6 May 1943 "U-125" was located by radar in thick fog, rammed by HMS "Oribi" and disabled, she was unable to dive. At 03:54 the U-boat was sighted by the Flower-class corvettes "Snowflake" and , and as "Snowflake" manoeuvred to attack, closing to 100 yards, the crew of "U-125", realising their indefensible position, scuttled the boat. The captain of "Snowflake" signalled the Senior Officer Escort, Lieutenant Commander Robert Sherwood, proposing to pick them up, and received the response: "Not approved to pick up survivors." "Snowflake" and "Sunflower" thereupon resumed their positions around the convoy, while the crew of "U-125" died in the Atlantic over the next few hours.