Advancing U.S.-Australian Combined Amphibious Capabilities

The demand for amphibious capabilities in the Indo-Asia-Pacific region reflects the operational and strategic challenges faced by the U.S. Marine Corps and Australian Defense Forces. Both nations have indicated the importance of deepening their strategic partnership, yet there has been a lack of clarity around the desired outcomes for and priority among the variety of cooperative activities.

Recognizing that the demand for amphibious capabilities in the Indo-Asia-Pacific region will likely continue to exceed the current capacity of any one nation, the CSIS International Security Program sought to explore the strategic and operational utility of various models for combined amphibious forces. The study first provides an overview of existing and projected ADF and USMC amphibious capability and capacity. Using data gathered from interviews with U.S. and Australian subject matter experts, the study examines two potential force options along five dimensions: range/duration, responsiveness, scale, breadth, and force protection. These options are evaluated against three mission sets varying in complexity. As the United States continues to face shortfalls in amphibious capacity and as Australia continues to advance its capabilities, this report provides a framework and recommendations through which to align strategic interests and advance a shared vision for combined amphibious operations.