By the invasion of Poland in 1939, the Polish Air Force had 35 Czaplas in five observation squadrons (out of twelve): No.'s 13, 23, 33, 53 and 63, each with seven aircraft. Squadrons were distributed among the field Armies. The remaining 30 Czaplas were initially in reserve. Several were used to supplement the combat units during the campaign (the mentioned squadrons and several others). In total, 49 Czaplas were used in units. Like the R-XIII, the Czapla was no match for any Luftwaffe fighter, bomber, or even reconnaissance aircraft, being much slower, and armed with only two machine guns. In spite of this, they were actively used for close reconnaissance and liaison tasks.