On September 11, 2001, the Marines of 1/1 were deployed on a WestPac (a deployment in an Amphibious Ready Group (ARG) making rounds in the Western Pacific) as part of the 15th MEU. Specifically, they were in Darwin, Australia on port leave. The Marines were recalled early from leave, shipped out, and began preparing for the first major combat operations since the first Gulf War. The flotilla sped to the Persian Gulf and was the first MEU to land in Afghanistan. Later, the 26th MEU would join them and assist in Operation Enduring Freedom.