[2][1][3] The U.S. Navy's 12th Naval District inspected Yellowstone with an eye toward using the ship as a depot collier during World War I and her assigned the identification number 2657.

After repairs to the damage she suffered in her collision with Moorish Prince, Yellowstone shifted to Pier 5 at Bush Terminal in Brooklyn on the morning of 15 October 1918 and over the next few days took on board 6,672 tons of general cargo – including automobiles and locomotives – earmarked for American forces in France.

[2] On 27 October 1918, Yellowstone got underway in convoy for France, "proceeding under confidential orders on [United States] Army transport duty to port of debarkation," St. Nazaire.

She discovered the water-logged Joseph P. Cooper of Mobile, Alabama, abandoned with her decks and cabin awash and with her forerigging gone and her forecastle smashed in.

Pumping oil through waste pipes in an attempt to break the force of the waves, Yellowstone wallowed through the storm while her engineers worked to repair the casualty.

By 0630, under tow by a French tug, she reached a safe basin, where she dropped both anchors and her crew began to take stock of the situation.

[2] Undocked upon completion of her hull repairs on 6 April 1919, Yellowstone loaded a return cargo of structural iron for use as ballast, barbed wire, and 6-inch (152-mm) artillery pieces.

On 10 December 1920,[c] she dragged her anchors due to high winds and ran hard aground off Ponta Delgada on São Miguel Island in the Azores.