Commissioned just before the thrust into the Mariana Islands, "Pasadena" completed shakedown and training during the summer of 1944, and on 25 September got underway for the Pacific theater. On 3 November she crossed the International Date Line and, continuing on, joined TF 38, the fast carrier force, at Ulithi at mid-month. She was part of TF38 as it sailed into Typhoon Cobra on 18 December 1944. Through the remainder of the year she participated in that force's operations against Luzon and Formosa in support of the Philippine campaign. In mid-January 1945, as the assault on Luzon pressed forward, the force sailed into the South China Sea and hit Japanese installations and shipping along the Indo-China coast and on Formosa. In February, the ships, now TF 58, moved against the Japanese home islands, then swung southeast to cover the landings on Iwo Jima, during which "Pasadena" added her guns to the bombardment group and performed patrol duties.