The Navy acquired Balboa Park free of charge and quickly converted the Park into a training facility for new recruits. Because Balboa Park was not next to a large body of water, and because the exposition buildings were too large and too poorly ventilated, the Navy had no facilities for nautical instruction for its sailors. The Navy adapted the available facilities, using the Lily Pond to train sailors how to row and maneuver small boats, as well as how to swim and float.
However, there was enough space around Balboa Park to host densely populated training exercises and events, such as parades, and the Navy personnel dances that were held in the Plaza de Panama.
A war hospital occupied the headquarters of the Balboa Park police, which was just south of the Plaza de Balboa. By the end of the war, November 11, 1918, the camp hospital looked like a city of canvas tents overfilling its capacity with more than 800 patients. The Secretary of the Navy at the time, Josephus Daniels, changed the name of the War Dispensary to Navy Hospital in May 1919. After World War I concluded, the Navy disbanded its facilities and left, and the Park's life dwindled.
As the buildings aged and went unused, it seemed as if San Diego would lose its unique buildings and heritage to decay.