When the Armistice of November 11, 1918 ended World War I, the regiment was no longer needed for combat in France, and it was relieved from assignment to the 12th Division on 31 January 1919.

Colonel James R. Lindsay commanded the regiment beginning in March 1919, and its subordinate units were subsequently posted to other bases and camps.

The regiment's primary wartime mission was to conduct a mobile defense of the beaches and inland sectors of the Pacific side of the Canal Zone.

The regiment was affiliated with the University of Puerto Rico ROTC and organized on 28 May 1929 at Rio Piedras as a "Regular Army Inactive" (RAI) unit with Regular Army personnel assigned to the ROTC detachment and Organized Reserve officers commissioned from the program.

[2] A Gold color metal and enamel device 1+1⁄4 inches (3.2 cm) in height consisting of a shield blazoned: Azure, semé of bees Or, a cross Argent, on a canton of the last two saltires of the field.