On 7 December, the 107th was ordered to proceed by train to St. John's, Newfoundland. On 10 December it boarded the  for the cross-Atlantic voyage, arriving on Christmas morning at Liverpool, England. After a brief rest, the squadron arrived at Southampton, England on the 29th, and crossed the English Channel to Le Havre, France. There, it then traveled by train to the Replacement Concentration Center, American Expeditionary Forces, St. Maixent Replacement Barracks, France, arriving on 2 January 1918. At St. Maixent the squadron was redesignated as the 801st Aero Squadron, and placed on camp duty for nearly two months. Finally, it was ordered to proceed to the Third Aviation Instruction Center at Issoudun Aerodrome, in central France, arriving on 21 February. Initially the squadron was assigned to the main airfield, working in the aircraft assembly and test departments. On 7 June, help was needed at Field No. 2, and the 801st was ordered to send 100 men to help put the field in better shape. Cooperating with another squadron, Field No. 2 was placed on an efficient basis as any field in the AEF.