The squadron was first activated in June 1943 at Geiger Field, Washington as one of the four original squadrons of the 452d Bombardment Group.
 Later that month, it moved to Rapid City Army Air Base, South Dakota and began to train with the Boeing B-17 Flying Fortress.
 It continued training with Second Air Force until December, when it began its movement to the European Theater of Operations.
The ground echelon staged through Camp Shanks and sailed on the RMS Queen Elizabeth  on 2 January 1944.
 The air echelon deployed via the South Atlantic air ferry route
The squadron established itself at RAF Deopham Green in January 1944, and began operations on 4 February 1944 with a strike on an aircraft assembly plant near Brunswick.
 Its strategic targets included railroad marshalling yards near Frankfurt, aircraft factories near Regensberg and Kassel.
the ball bearing factory at Schweinfurt and an oil refinery near Bohlen.
In September 1944, the squadron participated in the third shuttle mission, striking Chemnitz before landing in bases in the Soviet Union.

The 731st was occasionally diverted to support tactical operations.
 It hit airfields, V-weapon launching sites, bridges and other objectives in preparations for Operation Overlord, the invasion of Normandy.
 It bombed enemy positions to support Operation Cobra, the breakout at Saint Lo, in July 1944 and the attacks on Brest, France in August.
 It supported Operation Market Garden, airborne attacks attempting to establish a bridgehead across the Rhine in the Netherlands, in September and, during the Battle of the Bulge, struck German lines of communication.
 It struck an airfield to support Operation Varsity, the airborne assault across the Rhine in Germany.

Shortly before the end of the war, on 7 April, the squadron struck the jet fighter base at Kaltenkirchen, pressing the attack despite strong fighter opposition, earning a Distinguished Unit Citation.
 It flew its last mission of the war on 21 April against marshalling yards at Ingolstadt.

After V-E Day, in August 1945, the squadron returned to the United States (the ground echelon once again sailed on the RMS Queen Elizabeth) and was inactivated at Sioux Falls Army Air Field, South Dakota.
The squadron was first activated in June 1943 at Geiger Field, Washington as one of the four original squadrons of the 452d Bombardment Group.  Later that month, it moved to Rapid City Army Air Base, South Dakota and began to train with the Boeing B-17 Flying Fortress.  It continued training with Second Air Force until December, when it began its movement to the European Theater of Operations. The ground echelon staged through Camp Shanks and sailed on the RMS Queen Elizabeth  on 2 January 1944.  The air echelon deployed via the South Atlantic air ferry route
The squadron established itself at RAF Deopham Green in January 1944, and began operations on 4 February 1944 with a strike on an aircraft assembly plant near Brunswick.  Its strategic targets included railroad marshalling yards near Frankfurt, aircraft factories near Regensberg and Kassel. the ball bearing factory at Schweinfurt and an oil refinery near Bohlen. In September 1944, the squadron participated in the third shuttle mission, striking Chemnitz before landing in bases in the Soviet Union.
The 731st was occasionally diverted to support tactical operations.  It hit airfields, V-weapon launching sites, bridges and other objectives in preparations for Operation Overlord, the invasion of Normandy.  It bombed enemy positions to support Operation Cobra, the breakout at Saint Lo, in July 1944 and the attacks on Brest, France in August.  It supported Operation Market Garden, airborne attacks attempting to establish a bridgehead across the Rhine in the Netherlands, in September and, during the Battle of the Bulge, struck German lines of communication.  It struck an airfield to support Operation Varsity, the airborne assault across the Rhine in Germany.
Shortly before the end of the war, on 7 April, the squadron struck the jet fighter base at Kaltenkirchen, pressing the attack despite strong fighter opposition, earning a Distinguished Unit Citation.  It flew its last mission of the war on 21 April against marshalling yards at Ingolstadt.
After V-E Day, in August 1945, the squadron returned to the United States (the ground echelon once again sailed on the RMS Queen Elizabeth) and was inactivated at Sioux Falls Army Air Field, South Dakota.
731st Bombardment Squadron