Concepts & Programs HomeProgramsFocus Area 3: Naval IntegrationSeabasing

A U.S. Navy Landing Craft Air Cushion approaches the USNS John Glenn during exercise Pacific Horizon 2017, July 19, 2017. Pacific Horizon 2017 is a Maritime Prepositioning Force (MPF) exercise designed to train I Marine Expeditionary Force (MEF) and components of Naval Beach Group 1 (NBG-1) Marines and Sailors on arrival and assembly operations as well as follow-on Marine Air Ground Task Force actions to ensure that the right equipment, supplies and tools get to the right people to be employed in a crisis response, humanitarian assistance or amassing combat power ashore from sea. (U.S. Marine Corps photo by Lance Cpl. Roxanna Gonzalez)

Seabasing is defined as the deployment, assembly, command, projection, sustainment, reconstitution, and reemployment of joint power from the sea without reliance on land bases within the operational area. Seabasing incorporates the traditional naval missions of sea control, assured access, and power projection with an increased emphasis on maneuver from the sea.

Seabasing provides decision makers a range of flexible capabilities at a critical time, enabling access, freedom of movement, and action to most of the global flashpoints.

Specifically, seabasing expands access, reduces or eliminates the need to build up logistics assets ashore, reduces the operational demand for strategic sealift and airlift capabilities, and permits forward positioning of joint forces for immediate employment. These seabasing characteristics support national global strategic objectives and provide needed operational flexibility in an uncertain world. Through seabasing, we can establish expeditionary bases at sea in support of Geographic Combatant Commander (GCC) requirements.


Seven overarching principles are essential to seabasing operations.

  • Use the sea as maneuver space.
  • Leverage forward presence and joint interdependence.
  • Protect joint/coalition force operations.
  • Provide scalable, responsive, joint power projection.
  • Sustain joint force operations from the sea.
  • Expand access options & reduce dependence on land bases.
  • Create uncertainty for adversaries.


The seabase supports five overlapping lines of operation called CAESR: Force Closure, Arrival and Assembly, Employment, Sustainment, and Reconstitution. These lines of operation define the directional orientation of the force in time and space in relation to the enemy. They connect the force with its base of operations and its objectives.

Close - Closure of joint force capabilities to the area of crisis.

Assemble - Integration of scalable joint force capabilities within the sea base.

Employ - Employment of joint force capabilities from and supported by the sea base.

Sustain - Sustainment of selected joint forces afloat and ashore across the ROMO.

Reconstitute - Capability to recover, restore and redeploy joint combat capabilities within the maneuverable sea base for subsequent operations.


Traditionally, Marines conducted sea-based operations only from amphibious warfare ships. Maritime Prepositioning Ships (MPS) and Maritime Prepositioning Equipment and Supplies (MPE/S) were employed once they were assembled with fly-in echelon forces at major ports and airfield complexes ashore. Long perceived as a “break glass in time of war” capability, our maritime preposition forces are increasingly capable of conducting sea-based operations across the ROMO – from theater security cooperation (TSC) to supporting major combat operations (MCO) ashore. We continue to work with our Joint and Navy partners to address the interoperability challenges associated with sea-based operations and to take ever-greater advantage of the opportunities inherent in Seabasing.

Ultimately, the objective is to have a seabase capable of interfacing with joint assets and civilian agencies, as well as those from partner nations in order to support the increasing demand for sea-based support/ employment.

All seabasing platforms, amphibious and maritime prepositioning, need to improve for the future fight which will demand improved digital, vertical, and surface interoperability..



Naval Integration