Returning to New York 9 June 1944, Farquhar trained in antisubmarine warfare at Bermuda with the Wake Island hunter-killer group, then sailed on the Casablanca convoy route once more.

In September, she began patrols and convoy escort duty in the South Atlantic with the Mission Bay hunter-killer group.

She voyaged from Bahia, Brazil, to Dakar, French West Africa, and Cape Town, Union of South Africa, and during a submarine hunt off the Cape Verde Islands on 30 September, made a contact against which she and her sisters operated 6 days, finally sighting a large oil slick, but no other evidence of a sunken submarine.

Just 5 minutes after it was reported, she dropped 13 depth charges, set shallow, and both she and her sisters could make no further contact with the target.

Post-war evaluation revealed that she had been the last American ship to sink a submarine in the Atlantic in World War II, sending U-881 to the bottom.