R 041854Z DEC 25
MARADMIN 584/25
MSGID/GENADMIN/DC CDI QUANTICO VA//
SUBJ/PUBLICATION AND AVAILABILITY OF A CONCEPT FOR 21ST CENTURY
AMPHIBIOUS OPERATIONS//
REF/A/MSGID: MCO/CMC/YMD: 20231002//
NARR/REF A IS MCO 5401.1, CONCEPT GENERATION AND DEVELOPMENT//
POC/A. H. ARMSTRONG/LTCOL/MCWL FUTURES AND CONCEPTS/
ANDREW.ARMSTRONG@USMC.MIL//
GENTEXT/REMARKS/1. In July 2025, the
Commandant of the Marine Corps and the Chief of Naval Operations
approved a 21st Century Concept for Amphibious Operations (21CAO).
This concept is published at the following links:
1.a. Unclassified executive summary:
https:(slash)(slash)usmc.sharepoint-mil.us/sites/DCCDI/SitePages/
Final_Reports.aspx
1.b. Classified concept library: https:(slash)(slash)intelshare.
intelink.sgov.gov/sites/cdi/SitePages/FinalReportsLibrary.aspx
2. Background. Naval amphibious operations provide fleet commanders
with unique and asymmetric capabilities to deter aggression, respond
to crises and contingencies, and conduct combat operations when
necessary. The character of war continues to evolve. The exploitation
of additional domains for warfighting purposes and the corresponding
asymmetries directly influence the methods and means of executing
amphibious operations.
3. Purpose. 21CAO describes threat-informed ways and means for
conducting amphibious operations in the anticipated future operating
environment. These missions are required to accomplish
Joint Force Maritime Component Commander objectives against strategic
competitors and serve as a hypothesis from which to conduct further
investigation. These methods and means represent an offset to the
asymmetries future adversaries will depend on and serve as a
framework for capability development and force design.
4. Scope and Central Idea. 21CAO describes future amphibious
operations in the 2040-2045 time range. The concept is threat-
informed and globally-applicable. The concept’s central idea is that
future amphibious operations will contribute to campaigning by
seizing, defending, and denying key maritime terrain to support sea
control and conduct sea denial. 21CAO addresses diversified
amphibious operations including additional types of amphibious
operations, scalable amphibious operations, integrated stand-in
force and amphibious operations, streamlined command relationships,
and operationalized phasing.
5. Operating Concepts. 21CAO adds to the library of active Marine
Corps and Naval operating concepts:
5a. Littoral Operations in a Contested Environment (LOCE), 2017.
5.b. Concept for Expeditionary Advanced Base Operations (EABO), 2019.
5.c. A Concept for Stand-in Forces (SIF), 2021.
5.d. Concept for Naval and Special Operations Forces Operations
(CNSO), 2023.
5.e. Naval Concept for Distributed Maritime Logistics Operations
(DMLO), 2023.
5.f. Marine Corps Concept for Logistics (MCCL), 2024.
6. Collectively, the family of naval operating concepts is continuing
to guide Marine Corps modernization.
7. This MARADMIN is applicable to the Marine Corps Total Force.
8. Release authorized by Lieutenant General Eric E. Austin, Deputy
Commandant for Combat Development and Integration.//