The men chosen for the battalions were not ordinary inductees or volunteers—they all had construction-work backgrounds. The first batch of recruits who made the cut had helped build the Boulder Dam, national highways, and urban skyscrapers; had dug subway tunnels; and had worked in mines and quarries. Some had experience building ocean liners and aircraft carriers.
Approximately 325,000 men, from 60 different trades, ages 18 to 60, would go on to serve with the Seabees by the end of the war. The officers given the authority to command these men were also an elite crew, derived from the Civil Engineer Corps. Of the more than 11,000 officers in the Corps all together, almost 8,000 would serve with the construction units.