The Mojave was launched by the Union Construction Co., Oakland, California on 7 September 1921 as a United States Coast Guard cutter. She was sponsored by Miss Elizabeth Haske of Oakland and commissioned at Oakland on 12 December 1921.
First of the new Mojave class cutters that joined the fleet In 1921 for general duty, Mojave introduced the new principle of turboelectric drive. Assigned permanent station at Honolulu, she served with the Bering Sea Patrol, and assisted in enforcing the ban on deep-sea sealing. Upon completion of her Bering Sea tour Mojave transferred to Boston and, in company with cutters USCGC Modoc (WPG-46) and USCGC Tampa (WPG-48), took up Grand Banks ice patrol duties.
Mojave and her sister ships were gradually replaced by the new class of 2,200-ton cutters in 1930, although Mojave continued to operate out of Boston until 1933. She also occasionally took part in Coast Guard operations against the rumrunners between 1925 and 1930.
Weather patrols were instituted in 1940, and Mojave assumed rotating duty in 1941 as one of the Atlantic Ocean observation stations. This duty involved 21-day patrols in areas 10 miles square between Bermuda and the Azores. Prior to 1940 merchant ships had provided weather observation reports, but these had been curtailed when the outbreak of war forced ships of belligerent nations into radio silence.
For this reason the cutters operating out of Boston were relieved of their usual patrol and cruising duties so as to assume full-time weather patrol. When the cutters were transferred to the Navy 1 November 1941 the schedules of the weather patrol ships Mojave, Hamilton, Spencer, Bibb, and Duane were not affected.
Only when war developments increased demand for these large cutters elsewhere were they replaced by other, smaller craft taken over by the Coast Guard for such duties as weather patrol. By the end of the war there were 11 Coast Guard ocean stations in the Atlantic, acting as plane guards and radio beacons as well as weather reporters.
Mojave was assigned to the Greenland patrol in 1942, where she took part in convoy escort and rescue operations. While acting as escort for the slow group of Convoy SG—6 which had departed Sydney, Nova Scotia 25 August, she assisted in the rescue of 570 men from the torpedoed army transport Chatham. The escort and antisubmarine accomplishments of the cutters were truly vital to the winning of the Battle of the Atlantic.
Returned to the U.S. Treasury Department 1 January 1946, Mojave was caught up in the postwar demobilization. She decommissioned in 1947 and was sold in February 1948.
Mojave received one battle star for World War II service.