In 1936, the Germans sent a Luftwaffe force, the Condor Legion, to assist the Nationalists in the Spanish Civil War. Mölders volunteered for service, and arrived by sea in Cadiz on 14 April 1938. He was assigned to the 3. "Staffel" (3rd squadron) of "Jagdgruppe" 88 (J 88) commanded by "Oberleutnant" Adolf Galland. The unit, stationed at the Valencia–Ebro front, was equipped with the Heinkel He 51, but later switched to the Messerschmitt Bf 109 B-2. Mölders assumed command of the squadron on 24 May 1938, when Galland returned to Germany. He claimed his first aerial victory, shooting down a Polikarpov I-15 "Chato" ("Curtiss" to the Germans) near Algar, on 15 July 1938. Over the remaining months of the year, Mölders became the leading ace of the Condor Legion, claiming 15 aircraft in Spain: two I-15 "Curtiss", 12 I-16 "Rata" and one Tupolev SB (one "Rata" claimed on 23 September 1938 was not confirmed).