The Idaho emerged from post-shakedown repairs first, and her initial mission was to help ensure a peaceful election in the Panama Canal Zone. She embarked part of a Marine expeditionary force at Philadelphia on 20 June 1908, sailed for Panama, and landed them at Colon on 25 June. The New Hampshire (Battleship No. 25) transported the other contingent from New York, arriving on the 26th. Later that year, the Idaho proceeded to Norfolk, where a cage mainmast was stepped, the first installed in a U.S. battleship. The sisters then showed the flag at Philadelphia for Founder's Week, 3-9 October 1908.
Representing the United States at the inauguration of Cuban President Jos?
Miguel Gomez was the Mississippi 's first important assignment. She joined the Maine (Battleship No.10) at Key West, Florida, and reached Havana on 25 January 1909. Soon thereafter, as part of the Atlantic Fleet's Third Squadron, the sisters, along with the Maine and New Hampshire , met the returning Great White Fleet, then proceeded to Hampton Roads, where President Theodore Roosevelt reviewed the fleet on Washington's Birthday. While visiting her namesake state in May, the Mississippi steamed up the Mississippi River, reaching Natchez on the 20th. Then, at Horn Island on the 25th, she received a silver service from the state.
During the summer of 1910, the duo provided the Rhode Island Naval Militia with practical instruction on board a modern warship and allowed them to work alongside officers and men of the "regular" Navy. Both returned to New York City and soon thereafter proceeded to European waters with the Atlantic Fleet's Third Division, receiving a "most cordial welcome" at Gravesend, England and Brest, France. En route to Guantanamo after the European sojourn, they formed part of an "enemy" battleship force being sought by armored cruiser and scout divisions and a division of destroyers, an evolution that proved a useful exercise in tracking a heavier adversary and employing wireless communication to do so.
The Idaho cruised up the Mississippi in May-June 1911, then trained members of the Rhode Island Naval Militia on her return. The Mississippi embarked men of the New York Naval Militia later that same summer. Both ships then formed part of what Secretary of the Navy George Von Langerke Meyer termed the "largest and most powerful collection of vessels ever possible under the United States flag" at a fleet review at New York City. Some 100,000 people visited the ships, and two million more viewed them from vantage points on shore. President William Howard Taft, who reviewed the assemblage on 2 November 1911, declared that anyone who had seen the massed naval might "could not fail to be struck with its preparedness and with its high military efficiency, and must be proud of its personnel."
"Disturbed conditions" in Cuba dictated the Mississippi 's transporting part of a force of Marines there and landing them at El Cuero in June 1912, and while she went into the First Reserve on 1 August, her sister remained active. The Idaho took part in search and rescue operations in heavy weather in the aftermath of the collision between the steamer Noreuga and the lumber-laden schooner Glenlui off Cape Hatteras on 4 November. A few months later, unrest in the wake of General Victoriano Huerta seizing power in Mexico in February 1913 soon led to the Idaho steaming to Vera Cruz to support the Wilson administration's policy of keeping three or four battleships in Mexican waters.
The Idaho joined her sister ship in reserve at Philadelphia on 27 October 1913, but the pair did not remain in proximity for long, for the Mississippi was recommissioned five days after Christmas of 1913 to serve as an "aeronautic station ship." The Mississippi and the Orion (Collier No. 11) embarked men and loaded equipment to establish an "aeronautic center" and transported them from Annapolis, Maryland, to Pensacola, Florida, in January 1914. There they transformed a run-down naval station into a burgeoning training center for naval aviators.
When worsening relations between the United States and Huerta's Mexico led to the landing of Leathernecks and Bluejackets at Vera Cruz in April 1914, the Mississippi transported an aviation unit to that port. Lieutenant (junior grade) Patrick N. L. Bellinger, as one of only two qualified pilots (the other being the Mississippi 's commanding officer) flew for 46 straight days. Fired on at least twice, Bellinger retaliated with the only means at hand: a bar of Octagon soap that Lieutenant (junior grade) Richard C. Saufley, his passenger, released over Mexican troops.
While the Mississippi was making history, her sister, recommissioned on 16 March 1914, embarked midshipmen at Annapolis on 9 May, among them Lynde D. McCormick and Robert B. Carney, future Cold War chiefs of naval operations. The "Ida," one midshipman remembered, was "comparatively speaking" a "happy ship," steaming to Tangier, Gibraltar, and Naples with the Naval Academy Practice Squadron. She then proceeded independently to Villefranche, where she was turned over to the Greek government on 30 July 1914 to become the Lemnos. The Mississippi , meanwhile, had returned to Hampton Roads, where she also joined the Greeks on 21 July, becoming the Kilkis .
Bitter naval rivalry in the Balkans had led Greece and Turkey to seek battleships abroad. The former approached the United States and ultimately acquired the Mississippi and Idaho through an intermediary. The sale funds allowed appropriations for three new battleships, two of which perpetuated the names Mississippi (BB-41) and Idaho (BB-42). The third became the California , later renamed New Mexico (BB-40). The Turks ultimately received the formidable battle cruiser Goeben from the Germans.
Early during the April 1941 German assault against Greece, Stuka dive bombers pounded the port of Salamis. Ironically, the two unique battleships that had begun life in the same yard died in the same port, far from Philadelphia. German bombs sank the Kilkis; the Lemnos was driven aground in an attempt to prevent her total loss. Both ended their lives under the scrappers' torch.