USS Ajax, a 9250-ton (displacement) collier, was built in 1890 at Glasgow, Scotland. Under the name Scindia, she was purchased in the spring of 1898 for Navy service in the Spanish-American War. Commissioned in May 1898 as USS Scindia, in June and July she carried coal to the newly-established base at Guantanamo Bay, Cuba, to support combat operations nearby. Later in 1898, after the return of peace, the ship took a cargo of coal to Hawaii by way of Cape Horn, then went to California. Decommissioned at the Mare Island Navy Yard in May 1899, Scindia returned to active service in December of that year, and soon steamed across the Pacific to deliver coal to the Philippines. She continued on westward via the Indian Ocean and Suez Canal route, reaching the U.S. East Coast after picking up a coal cargo at Cardiff, Wales. At the beginning of January 1901, during the course of this voyage, Scindia was renamed Ajax.

Out of commission for overhaul between March and October 1901, USS Ajax made two more voyages to the Philippines up to September 1903, then operated in Far Eastern waters until late in 1904, when she returned to the U.S. The ship was laid up for most of 1905 and all of 1906, spent nearly all of 1907 in the East Coast area, and in December of that year began a long cruise supporting the "Great White Fleet" during its voyage around the World. Arriving back at Norfolk, Virginia, in February 1909, Ajax was in the Atlantic area, in both active and reserve status, for nearly four years. In December 1912 she began another deployment to the Philippines, this time transporting the submarines B-2 and B-3.

Ajax served with the Asiatic Fleet for the remainder of her career, initially carrying coal and other cargo to support the Navy's operations in that region. She was designated AC-14 in mid-1920, when the Navy implemented its hull number system, and was receiving ship at the Cavite Navy Yard, near Manila, during much of the early 1920s. In addition, during part of 1923 Ajax was stationed at Chefoo, China, as a submarine tender. Duty as an aircraft tender followed in 1924-1925, accompanied by redesignation to AG-15 in July 1924. The now quite-elderly USS Ajax was decommissioned in July 1925 and sold at Cavite a month later.