School of Infantry MCT | United States Marine Corps The School of Infantry (SOI) is the second stage of initial military training for enlisted United States Marines after Recruit Training. At SOI, Marines with the Military Occupational Specialty of infantry (0300 occupational field) are trained at the Infantry Training Battalion (ITB), while all non-infantry Marines are trained in basic infantry and combat skills at the Marine Combat Training Battalion (MCT Bn). SOI marks a transition in the professional training of entry-level students from basically trained Marines to combat-ready Marines. Follow Us On These Places For Update https://twitter.com/TimesArchives Credit: Sgt. Manuel A. Serrano, Cpl. Andre Heath, LCpl. Dylan Chagnon