Shoup was assigned to the 1st Provisional Marine Brigade, which was moved to Iceland in May 1941, supporting an occupation there to prevent Nazi German forces from threatening it.
Replacing the outgoing British 49th (West Riding) Infantry Division, the brigade continued to garrison the country for several months, and he was there with the Headquarters Company at the time of the Japanese attack on Pearl Harbor in December 1941.
For his service in Iceland, he was awarded the Letter of Commendation with Commendation Ribbon.
In February 1942 he was given command of the 2nd Battalion, 6th Marines.
With the United States at war, 1st Provisional Marine Brigade moved to New York City, New York, in March, and was disbanded.
Shoup moved with his battalion to Camp Elliott in San Diego.

In July 1942, Shoup was named as operations and training officer (then known as D-3) of the 2nd Marine Division, and he was promoted to lieutenant colonel in August 1942.
The following month he accompanied the division to Wellington, New Zealand, aboard SS Matsonia and oversaw much of its training there.
He was also briefly attached to the 1st Marine Division in October 1942 as an observer during the Guadalcanal campaign, then to the 43rd Infantry Division on Rendova Island during the New Georgia Campaign in June 1943.
During the latter assignment, Shoup was wounded in action and evacuated.
Still, from these experiences he observed amphibious warfare techniques which would be useful later in the war.
Shoup was assigned to the 1st Provisional Marine Brigade, which was moved to Iceland in May 1941, supporting an occupation there to prevent Nazi German forces from threatening it. Replacing the outgoing British 49th (West Riding) Infantry Division, the brigade continued to garrison the country for several months, and he was there with the Headquarters Company at the time of the Japanese attack on Pearl Harbor in December 1941. For his service in Iceland, he was awarded the Letter of Commendation with Commendation Ribbon. In February 1942 he was given command of the 2nd Battalion, 6th Marines. With the United States at war, 1st Provisional Marine Brigade moved to New York City, New York, in March, and was disbanded. Shoup moved with his battalion to Camp Elliott in San Diego.
In July 1942, Shoup was named as operations and training officer (then known as D-3) of the 2nd Marine Division, and he was promoted to lieutenant colonel in August 1942. The following month he accompanied the division to Wellington, New Zealand, aboard SS Matsonia and oversaw much of its training there. He was also briefly attached to the 1st Marine Division in October 1942 as an observer during the Guadalcanal campaign, then to the 43rd Infantry Division on Rendova Island during the New Georgia Campaign in June 1943. During the latter assignment, Shoup was wounded in action and evacuated. Still, from these experiences he observed amphibious warfare techniques which would be useful later in the war.
David M. Shoup