After the attack on Pearl Harbor brought the USA into World War II, the squadron was transferred to the West Coast, flying anti-submarine patrols from Muroc AAF, California from December 1941 to the end of January 1942.

Leaving the B-18s at Muroc, the squadron moved to the South Pacific where it flew its first combat missions from Garbutt Field, Townsville, Australia, against Rabaul, New Britain.

[3] The squadron was again re-equipped, with Consolidated B-24 Liberators, in early 1944, then returned to combat status on 10 March 1944 with a raid against Manus Island.

In June 1945, for a week, the B-24s flew from Puerta Princesa, Palawan Island, to hit targets on Borneo in support of Australian forces landing there.

It deployed to England in November 1946, where it flew training missions to Accra, West Africa, Aden, Yemen, and Arabia, returning in February 1947 to Smoky Hill AFB, then to March Air Force Base, California in May.

The 19th again deployed to England from November 1949 to February 1950 where the squadron flew training sorties to Germany and Dhahran, Saudi Arabia.

[3] Back at March AFB, the 19th trained Boeing B-29 Superfortress crews to be sent to the Far East Air Forces for combat duty in Korea.

The 19 BS made its last deployment to England between December 1953 and March 1954, flying training missions to Sidi Slimane and French Morocco.

In November 1957, the 19th BS received a forward alert obligation, initially sending five B-47s to Eielson Air Force Base, Alaska, for six months of cold weather training, then rotating a single aircraft with aircrew for two to four weeks at a time.

The 19th also flew increased missions during the Tet Offensive of 1968 and shared in a Navy Presidential Unit Citation for support to U.S. Marines defending Khe Sanh from January to March 1968.