After overhaul and final trials, "Saury" got underway on 4 December for the West Coast. On 12 December, she transited the Panama Canal and, nine days later, joined Submarine Division (SubDiv) 16 of Submarine Squadron (SubRon) 6, at San Diego, California. Upkeep, exercises, and services as a target for surface units took her through March 1940. In April, she sailed west to participate in Fleet Problem XXI, an eight-phased problem simulating an attack on the defense of the Hawaiian area and the destruction of one fleet prior to the concentration of another.