After the American entrance into World War I, Utah was stationed at Berehaven in Bantry Bay, Ireland, where she protected convoys from potential German surface raiders.

In 1931, Utah was demilitarized and converted into a target ship and re-designated as AG-16, in accordance with the terms of the London Naval Treaty signed the previous year.

The ship was powered by four-shaft Parsons steam turbines rated at 28,000 shp (20,880 kW) and twelve coal-fired Babcock & Wilcox boilers, generating a top speed of 20.75 kn (38.43 km/h; 23.88 mph).

[1] She then conducted a shakedown cruise that stopped in Hampton Roads, Santa Rosa Island, Pensacola, Galveston, Kingston, Jamaica, and Guantánamo Bay, Cuba.

While en route to Mexico on 16 April, Utah was ordered to intercept the German-flagged steamer SS Ypiranga, which was carrying arms to the Mexican dictator Victoriano Huerta.

Ypiranga's arrival in Veracruz prompted the US to occupy the city;[2] Utah and her sister ship Florida were the first American vessels on the scene.

After arriving in Ireland, Utah was assigned as the flagship of Battleship Division 6 (BatDiv 6), commanded by Rear Admiral Thomas S. Rodgers.

[2][3] Following the end of the war in November 1918, Utah visited the Isle of Portland in Britain, and escorted the liner George Washington in December, which carried President Woodrow Wilson to Brest, France, for the post-war peace negotiations at Versailles.

[2] In early 1924, Utah took part in the Fleet Problem III maneuvers, where she and her sister Florida acted as stand-ins for the new Colorado-class battleships.

[4] Later that year, Utah was chosen to carry the US diplomatic mission to the 9 December centennial celebration of the Battle of Ayacucho, which had taken place on that date in 1824.

She left New York on 22 November with General of the Armies John J. Pershing aboard for a goodwill tour of South America; Utah arrived at Callao, Peru, on 9 December.

At the conclusion of Pershing's tour, Utah met him at Montevideo, Uruguay, and then carried him to other ports, including Rio de Janeiro, Brazil, La Guaira, Venezuela, and Havana, Cuba.

This time, she picked up President-elect Herbert C. Hoover and his entourage in Montevideo, and transported them to Rio de Janeiro in December, and then carried them home to the United States, arriving in Hampton Roads on 6 January 1929.

According to the terms of the London Naval Treaty of 1930, Utah was converted into a radio-controlled target ship, to replace the older North Dakota.

[2] On 7 April, Utah left Norfolk for sea trials to train her engine room crew and to test the radio-control equipment.

Her electric motors, operated by signals from the controlling ship, opened and closed throttle valves, moved her steering gear, and regulated the supply of oil to her boilers.

On 9 June, she again left Norfolk, bound for San Pedro, Los Angeles, where she joined Training Squadron 1, Base Force, United States Fleet.

To perform this task, she was equipped with a new 1.1-inch (28 mm)/75 caliber anti-aircraft gun in a quadruple mount for experimental testing and development of the new type of weapon.

[2] Utah returned to the Atlantic to participate in Fleet Problem XX in January 1939, and at the end of the year, she trained with Submarine Squadron 6.

Shortly before 08:00 on the morning of 7 December, some crewmen aboard Utah observed the first Japanese planes approaching to attack Pearl Harbor, but they assumed they were American aircraft.

At the same time sixteen Nakajima B5N torpedo bombers from the Japanese aircraft carriers Sōryū and Hiryū flew over Pearl City approaching the west side of Ford Island.

However six of the B5Ns from Soryu led by Lieutenant Nakajima Tatsumi broke off to attack Utah, not recognizing that the shapes over the barbettes were not turrets, but boxes covering empty holes.

As the crew began to abandon ship, one man—Chief Watertender Peter Tomich—remained below decks to ensure as many men as possible could escape, and to keep vital machinery running as long as possible; he received the Medal of Honor posthumously for his actions.

Her rusting hulk remains in Pearl Harbor, partially above water;[2] the men killed when Utah sank were never removed from the wreck, and as such, she is considered a war grave.

The memorial consists of a 70-foot (21 m) walkway made of white concrete, which extends from Ford Island out to a 40 by 15 ft (12.2 by 4.6 m) platform in front of the ship, where a brass plaque and a flagpole are located.