During the war, the division had five Seabee Battalions posted to it. the 6th NCB was attached to the 1st Marine Division on Guadalcanal. They were followed by the 19th Naval Construction Battalion (NCB) which was assigned to the 17th Marines as the third battalion of the regiment. They landed at Cape Gloucester with the division. The 17th Marines were inactivated with the 19th NCB being reassigned. After that, the 33rd NCB was posted to the 1st for the assault on Peleliu and they were replaced by the 145th NCB for the invasion of Okinawa. (see:Seabees) On Peleliu, the 17th Special NCB(segregated) was assigned to the 1st Pioneers as shore party. Together with the 16th Marines Field Depot(segregated) they helped evacuate wounded and bury the dead for the 7th Marines. On the first night of the assault, nearly all of the 17th Seabees volunteered to hump ammo to the frontlines. They also reinforced the Marines in sections where directed, were used to crew a 37mm, and were utilized for several days. For their efforts, they received an official "well done".