Deployed to Kunming Airport, China in March 1943, becoming the heavy bombardment arm of the new Fourteenth Air Force.

Air echelon deployed to the CBI via the South Atlantic Transport route via Brazil, then across central Africa and Middle East to Karachi, India.

Once established in India, group aircraft made many trips over the Himalayan Mountains (The Hump) to Southeastern China from the Assam Valley of India airlifting gasoline, oil, bombs, spare parts, and other items the group needed to prepare for and then to sustain its combat operations.

From its main base at Kunming and later Hsinching Airfield, the 308th carried out long range strategic bombardment of enemy targets in China in support of Chinese ground forces.

The group attacked airfields, coalyards, docks, oil refineries, and fuel dumps in French Indochina; mined rivers and ports; bombed shops and docks at Rangoon; attacked Japanese shipping in the East China Sea, Formosa Strait, South China Sea, and Gulf of Tonkin.

Received a Distinguished Unit Citation for an unescorted bombing attack, conducted through antiaircraft fire and fighter defenses, against docks and warehouses at Hankowon 21 August 1943.

Major Horace S. Carswell, Jr. was awarded the Medal of Honor for action on 26 October 1944 when, in spite of intense antiaircraft fire, he attacked a Japanese convoy in the South China Sea; his plane was so badly damaged that when he reached land he ordered the crew to bail out; Carswell, however, remained with the plane to try to save one man who could not jump because his parachute had been ripped by flak; before Carswell could attempt a crash landing, the plane struck a mountainside and burned.

After the Japanese Capitulation in August, the group remained in India in support United States forces in the CBI.