After refit and a brief training period, "Barbero" departed Fremantle on her second war patrol on 26 October. On this patrol, Comdr. Hartman also assumed command of a coordinated attack group (nicknamed a wolfpack) consisting of "Barbero", , and . The first phase of this two-part patrol lasted from 26 October until 15 November. It was conducted in the Makassar Strait and in the area west of Mindoro. On 2 November, after a lively passage of Lombok Strait during which picket boats and shore batteries fired on her, "Barbero" sank her first ship, a 2,700-ton transport loaded with troops. On 8 November, she sent a 7,500-ton tanker to the bottom during a coordinated attack on a small convoy (consisting of submarine chasers "CH-7" and "CH-8" escorting oilers "Shimotsu Maru" and "Nichinan Maru No. 2") carried out in cooperation with "Redfin". "Redfin" received credit for sinking the other tanker in the convoy.