He returned to France in the summer of 1946, charged with the responsibility of recruiting and training volunteers for a colonial parachute battalion that was being formed for combat in Indochina against the Viet Minh. Trinquier returned to Indochina with the 2nd Colonial Commando Parachute Battalion (2e BCCP), during November 1947. The battalion was assigned to Lai Thieu, a refuge for the 301st Viet Minh Regiment, located around 20 km from Saigon. He took part, as second-in-command, in operations in Cambodia and on the Plain of Reeds in southern Vietnam. He took command of the battalion when its commander, Major Dupuis, was killed in action on 9 September 1948, and was promoted to Major on 1 October. Leading the battalion in combat in central Annam and the area around Saigon, he became aware of the inefficiency of the operations launched by the French high command and proposed to General Pierre Boyer de Latour du Moulin, the commander of the French forces in southern Vietnam, a new approach to pacifying areas with strong Viet Minh presence. Trinquier's troops occupied the terrain and laid ambushes against the Viet Minh at night instead of the normal policy of taking a few positions, where refuge could be taken at night and then reopening the roads in the morning. Trinquier's tactics proved effective, reassured people and pacified the Laï Thieu area. On 12 December 1949, after thirty airborne operations and numerous ground operations, Trinquier and the battalion embarked on "Pasteur", a French transport ship, and returned to France.