In November, the squadron moved to MacDill Field, Florida, where it trained with Boeing B-17 Flying Fortresses under Third Air Force.

[1][5] The 815th deployed to the Mediterranean Theater of Operations, where it became part of Fifteenth Air Force at Sterparone Airfield in Southern Italy.

[7] The squadron engaged in long-range strategic bombardment of enemy military, industrial and transport targets, including factories, oil refineries, marshalling yards, airfields, and troop concentrations in Italy, France.

[5] In June 1944, the squadron participated in a shuttle mission, departing Italy and landing in the Soviet Union, attacking targets en route and on the return flight.

On 18 July 1944 the squadron, along with the other elements of the 483d Group, bombed the objective, an airfield and installations at Memmingen, engaging numerous enemy aircraft in the target area despite a lack of cover from its planned fighter escort.

Between April 1953 and September 1954, the squadron aided the French Air Force in Indochina by training personnel and hauling supplies.

[5] In 1958, the 483d Group was inactivated as Far East Air Forces converted to the dual-deputy organizational model and the squadron was reassigned directly to the wing.

[1] It continued intratheater transport operations, also flying to locations in the Philippines, Thailand and Indochina, supporting United States civilian and military personnel assigned to the region.

As the United States increased its combat presence in Indochina in the early 1960s, made frequent flights to airfields in South Vietnam and to locations within the country, periodically deploying crews and aircraft there.

The 815th was selected in May 1999 as the first unit in the U.S. Air Force to take delivery of the C-130J variant and participated heavily in writing the book for "J" model operations.

On 21 March 2013, the 403rd Wing announced that its C-130J aircraft would be redeploying to Pope Air Force Base, North Carolina, beginning in October 2013 in preparation for inactivation of the 815th.