By 29 June, the squadron had relocated to Saints Aerodrome in the Marne Sector to participate in the Battle of Château-Thierry. The 12th encountered intense opposition in the air from a concentration of German squadrons equipped with the most advanced Fokker aircraft. Encounters with up to 20 enemy aircraft on a patrol was a daily occurrence. On 5 July, the squadron moved again to a neighboring field at Francheville in support of the 26th Division, but because of its distance from the front, what would later be known as a "forward operating location," or FOL, was established at Ferme de Moras Aerodrome. Two 12th Squadron aircraft and two from the 88th Aero Squadron were flown to it at daybreak each day and held ready for developing requirements. The Allied counteroffensive was launched on 18 July and the squadron's support was vital in photographing targets ahead of the advance according to priorities set by corps intelligence. It was during this operation that oblique photography, sometimes from as low as 400 meters, began to be used; previously all photos had been vertical. The Ferme de Moras location was upgraded to a full airfield on 22 July when the squadron occupied it to participate in the Chateau-Thierry offensive, during which it lost five officers.On 28 July 1918 the Squadron had two Salmson Observation aircraft shot down near Villers Sur Fere:2/Lt AP Baker WIA/PoW and 2/Lt JC Lumsden KIA, {shot down by German ace Carl Bolle (27th victory); and  Pilot John C. Miller died of wounds and Observer Lt. Stephen W. Thompson was shot in the leg.(Shot down by Lt Sergy  Frommherz, (10th Victory) of Jagdstaffel 2