[1] It is capable of projecting expeditionary striking power in the maritime, littoral, and inland environs in support of U.S. national interests.

[2] The mission of Expeditionary Strike Group 3 is to provide amphibious expertise and a deployable staff for combat and contingency operations in support of the nation's interests and maritime strategy.

PhibGru 3 was probably active during World War II and was definitely active by 1945; at Eniwetok on 7 September 1945, revised orders directed USS Bayfield (APA-33) to Tacloban in the Philippines, where she arrived on 14 September and reported to Commander Amphibious Group 3 for duty in the occupation of Aomori, Japan.

As flagship for Rear Admiral Lyman A. Thackrey, Commander, Amphibious Group 3, she acted as standby for Mount McKinley (AGC-7) during the invasion of Inchon, Korea, and coordinated and controlled the logistics operations.

This event marked the first time in history that a United States Marine Corps officer took command of a naval formation.

To support the OIF II Force Rotation Plan and the First Marine Expeditionary Force's deployment to relieve the 3d Armored Cavalry Regiment and the 82nd Airborne Division in Iraq, Commander Amphibious Group 3, Rear Adm. W. C. Marsh, and his San Diego–based staff deployed into the Fifth Fleet Area of Operations.

Marsh assumed duties as Commander Task Force 51 (CTF 51) and began overseeing amphibious operations in the area.