At the start of United States of America's involvement in the First World War, five sites in Ireland; Queenstown, Wexford, Lough Foyle, Whiddy Island and Berehaven were identified to be operated by the United States Navy in support of allied operations against enemy submarines.
Local Irish labor and American construction teams worked on the site, building a control tower that still stands, accommodation and workshops, and a concrete slipway for beaching the aircraft – this is still in existence.
In July 1918, the first Curtiss H-16 flying boats arrived in Londonderry. These had been stripped down and had to be re-assembled, a task completed by 22 August when training began. On 1 September 2018, the base became operational. Between 3 September and 6 November the flying boats completed 27 patrols – flying was possible only on 31 days. The longest patrol, on 24 October, was over six hours.
On 19 October 1918, while escorting a 32-ship convoy in the Lough Foyle sector off Northern Ireland, ENS George S. Montgomery sighted and successfully attacked an enemy submarine stalking the convoy. His bombs hit within 30 feet of the periscope and brought heavy turbulence and oil to the surface. For “probably damaging” the submarine and saving the convoy from attack.
With the end of the war, the U.S. Naval Air Stations in Ireland were no longer required. The Anti-submarine warfare patrols were discontinued and the aircraft were grounded and disarmed as NAS Lough Foyle closed on 22 February 1919.