An Expeditionary Strike Group (ESG) is a United States Navy unit that adds surface combatant warships and submarines to the amphibious warfare and limited air operations capabilities of an Amphibious Ready Group. The additional ships of an ESG are effectively the escort of a Carrier Strike Group (CSG). Without an ARG and possibly without the submarine, they may be called a surface action group.
The ESG organization allows the Navy to put more operational units at sea than is possible by the limit imposed by the number of aircraft carriers.
Typically, it will be commanded by a rear admiral senior to the commodore of the ARG. This admiral may be from the surface, submarine, or aviation communities, as opposed to the tradition, now being changed, that a CSG had to be commanded by an aviator.
The combat vessels of an ESG include:
They may be accompanied by a replenishment ship.