Upon being commissioned, she underwent a shakedown cruise off of San Diego. On 15 April 1944, "Saginaw Bay" loaded aircraft and their pilots from Terminal Island for transport to Hawaii. She arrived at Pearl Harbor on 21 April, where she unloaded her cargo in exchange for damaged planes, before returning to Alameda, California. She proceeded to conduct pilot qualifications off the coast of San Diego throughout May and early June, during which a FM-2 fighter crashed into the sea, killing its pilot. After completing her exercises, she underwent a second replenishment aircraft ferry mission, arriving at Pearl Harbor on 5 July.