After taking on Army cargo at Oakland, she departed the west coast early in August 1950 and arrived at Yokohama on the 29th to discharge her cargo and complete outfitting for her return to the role of attack cargo ship. After combat loading and embarking Army and Navy personnel, "Thuban" proceeded to Kobe and, on 11 September 1950, got underway with TG 90.2 bound for Operation "Chromite" – the assault on Inchon. En route to its destination, the task group encountered heavy seas as it skirted a typhoon; and "Thuban" was forced to fall behind to repair a hydraulic line carried away by rough seas. Repairs completed, "Thuban" rejoined the task group and, on the 15th, approached the outer transport area at Inchon. That day, her boats joined in the first assault waves; and, in the days that followed, the veteran attack cargo ship discharged personnel, cargo, and equipment in support of the invasion.