II./KG 55 flew combat operations over Bobruisk-Sloboda-Minsk in support of Army Group Centre. From later June, and for several weeks, it flew night bombing raids on Smolensk, 28/29 June 1944. It left Deblin for Inowroclaw on 26 July. It could still muster 35 bombers by 26 June and bombed targets at Molodechno, northwest of Minsk on 23 July. The raids cost KG 55 five bombers on 5 July which took the total to 14 destroyed in just six days of action from 29 June. Attacks on the Vistula bridges at Warsaw and Baranów Sandomierski followed from 1–12 August. Its force was reduced to 31 He 111H-16s by 1 September. It withdrew to Germany to carry out air-supply flights to German Garrisons in isolated French ports from 10 to 12 September after Operation Overlord and Battle for Normandy, and liberated the bulk of France and Belgium over June–September 1944. From Hohensalza it transferred to Zellhausen, where it was disbanded and reformed into fighter unit II. 55 on 1 October 1944.