381ECSS is an expeditionary combat support squadron of the RAAF formed at RAAF Williamtown, NSW in May 1998. It is a fully deployable airbase operations unit that provides airbase-specific operations support and common 'close' combat support functions to one or more collocated flying units at a forward operating base. Effectively an ECSS runs the base support to ensure lodger flying units are able to concentrate on the projection of the required air power to support directed RAAF missions. 381ECSS airbase operations and combat support functions include: