By mid-1968, the SEAL Teams were fielding 12-man platoons, each comprising two squads of six men; most SEAL missions conducted in Vietnam were squad-sized operations. Generally, four or five platoons, at any given time, were deployed to South Vietnam. SEAL platoons were never assigned permanently to Vietnam; instead, they were deployed on temporary duty assignments, usually for a period of about 6 months, with many of the men making several tours. From: US Navy | Ghosts of the Battlefield