Completing her repairs at Boston in mid-March, she conducted refresher training at Casco Bay, Maine, before heading back to the Mediterranean at the end of the third week in April. She stopped at Gibraltar on the last day of that month and arrived at Oran on May Day. The ensuing three months saw her operating out of Oran conducting antisubmarine patrols of the approaches to that port. While operating with a hunting group composed of , , and in mid-May, "Woolsey" experienced her third and last encounter with a German U-boat. A report of torpedo tracks from a newcomer to the Mediterranean, , brought DesDiv 25 to the area between Oran and Cartagena early on 17 May to commence a two-day search and destroy mission. During the night of 18 and 19 May, the four destroyers split themselves into two search groups and began searching a possible submarine track 10 miles to each side of it. About an hour and 40 minutes into the mid-watch, the four warships received word that a plane had spotted the submarine some 10 miles ahead of "Niblack" and "Ludlow". Those two ships charged to the attack; and, by the time "Woolsey" arrived on the scene with "Benson" and , the two destroyers had succeeded in forcing the U-boat to surface after delivering 11 depth charge attacks over the space of four hours. Immediately, all five destroyers opened fire on the submarine while a British Wellington bomber dropped depth bombs from a low altitude near "U-960". The German submarine suffered a number of hits before submerging again. "Niblack" responded with more depth charges. That attack evidently rung the death knell for "U-960" for she immediately resurfaced, and her crew scrambled off just as she made her final plunge at about 07:15 on 19 May. The destroyers picked up the U-boat's captain and 21 of her crew. "Niblack" and "Ludlow" received official credit for sinking the enemy submarine.