She was launched on 26 March 1914, sponsored by Mrs. Thomas Gaines Roberts, and commissioned on 9 September at Boston, Massachusetts.

Steaming to Newport, Rhode Island, on 16 November, K-6 joined the 4th Division, Atlantic Torpedo Flotilla, for shakedown and training.

Following overhaul at Philadelphia, Pennsylvania, she departed New London on 12 October 1917, and steamed via Halifax, Nova Scotia, for patrol duty in the Azores.

For more than a year they patrolled the surrounding ocean, searching for U-boats and surface raiders and preventing them from using the islands as a haven.

After the surrender of Germany, K-6 sailed for the United States on 21 November arriving Philadelphia via Bermuda on 13 December.