Her keel was laid down by Fore River Shipbuilding Company in Quincy, Massachusetts, as Cachalot, making her the first ship of the United States Navy to be named for the cachalot, another name for the sperm whale, but on 17 November 1911, during construction, she was renamed K-2.

After trials and exercises in New England waters throughout the spring and summer of 1914, K-2 joined 4th Division, Atlantic Torpedo Flotilla, Newport, Rhode Island, on 9 October.

[1] As World War I raged in Europe, guarding the vital shipping lanes across the Atlantic Ocean became imperative.

She was among the first U.S. submarines to engage in patrol duty during the war, and cruised in these waters searching for enemy U-boats.

K-2 continued these vital patrols until 20 October 1918 when she sailed for North America arriving Philadelphia, Pennsylvania, on 10 November to resume coastal operations.