Naval Mobile Construction Battalion 25
Naval Mobile Construction Battalion 25 is a United States Navy Reserve Seabee unit headquartered at Port Hueneme, California.
Last updated August 31, 2026
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Overview
Naval Mobile Construction Battalion 25, commonly known as NMCB 25 or 25 NCB, is a United States Navy Reserve Seabee unit. Unlike a commercial brand, it is a military engineering organization whose identity represents a continuing naval construction command rather than a consumer or corporate product. The battalion is headquartered at Naval Base Ventura County, Port Hueneme, California, and forms part of the Navy’s Naval Construction Force Reserve. The unit’s lineage began during the Second World War. The 25th Naval Construction Battalion was commissioned on 13 September 1942 at Camp Bradford, Virginia, and moved to the Port Hueneme area. Soon afterward, headquarters and several companies were transferred to the Marine Corps, where elements of the battalion were integrated into Marine engineer and combat formations. The organization was redesignated as the Third Battalion of the 19th Marines and operated with the 3rd Marine Division. One company was used as the nucleus of the separately organized 53rd Naval Construction Battalion, creating an enduring historical association between the two units. During the Pacific War, personnel from the battalion served in the New Zealand, Guadalcanal, Bougainville, and Guam operations. On Bougainville, Seabees worked alongside Marine formations on roads, logistics routes, and other combat-support infrastructure. In the Guam campaign in July 1944, the battalion landed under fire and supported the 3rd Marine Division’s assault teams. Its heavy construction equipment, including bulldozers capable of clearing jungle and improving roads, was especially valuable in moving supplies, evacuating casualties, and positioning artillery. The battalion also contributed to construction work associated with Harmon Airfield. Its wartime experience demonstrated the importance of combining naval construction expertise with amphibious assault forces. The wartime unit was returned to Navy administration in August 1944 and was eventually decommissioned in November 1945, after its Guam work orders were transferred to another naval construction battalion. NMCB 25 was recommissioned in October 1961 at Davisville, Rhode Island, as part of the Naval Construction Force Reserve. From 1995 through 2014, its homeport was Fort McCoy, Wisconsin, following an earlier period at Glenview, Illinois. The headquarters later moved to Port Hueneme, where the reserve battalion remains based. In its modern role, NMCB 25 provides trained Seabee personnel for expeditionary construction, engineering support, infrastructure repair, contingency operations, and humanitarian assistance. Recorded deployments and missions include Iraq in 2006, Guantanamo Bay from 2009 to 2010, Haiti after the 2010 earthquake, Afghanistan in 2014, and Afghanistan in 2019. The battalion’s service record includes repeated Navy 'E' awards and other unit recognitions, including Admiral Perry Awards in 1996, 2006, and 2019. Its history combines combat engineering, expeditionary construction, disaster response, and reserve-force mobilization.
History
The 25th Naval Construction Battalion was commissioned on 13 September 1942 at Camp Bradford, Virginia. It was sent to the Port Hueneme area, the principal West Coast center for Seabee organization and training. On 31 October, the battalion’s headquarters and Companies A, C, and D were transferred to the Marine Corps and sent to Camp Elliot near San Diego. Because Marine battalions used a different company structure, Company B was separated and used as the nucleus for the 53rd Naval Construction Battalion. The two units subsequently remained closely associated in wartime assignments. The remaining elements of the 25th were incorporated into Marine formations of the 3rd Marine Division. Companies and headquarters personnel were distributed among the 9th, 21st, and 3rd Marine regimental combat teams. In early 1943, detachments traveled through the Pacific to New Zealand and other staging areas. In June, the battalion was detached from Marine administration and restored to a headquarters-and-construction-company structure before being sent to Guadalcanal in preparation for the Bougainville campaign. On 1 November 1943, 386 enlisted personnel and officers landed on Bougainville under fire; a further 317 enlisted personnel and six officers arrived by 28 November. There the battalion worked with the 53rd and 71st Naval Construction Battalions. Its tasks included building and improving routes needed to move supplies and support advancing forces. The battalion returned to Guadalcanal in early 1944. On 11 April, after the 19th Marines was decommissioned, the 25th was released from the 3rd Marine Division’s administrative control and redesignated again as the 25th Naval Construction Battalion, while retaining operational ties to Marine forces. The next major operation was the invasion of Guam. On 21 July 1944, 621 men and 23 officers landed under fire with the 3rd Marine Division. Company elements were assigned to the division’s regimental combat teams and served as part of shore parties. Lieutenant Commander Whelan directed the shore party for the 3rd Marine Regiment on Red Beaches 1 and 2, while Lieutenant Commander Brett W. Walker held a comparable leadership role on the Blue and Green Beaches. Both received Bronze Stars for their leadership. Guam’s dense jungle and difficult terrain made heavy equipment indispensable. Seabee bulldozers were used to clear and improve roads, move supplies toward the front, assist casualty evacuation, and prepare positions for artillery. The battalion’s construction equipment was more capable for this work than much of the Marine equipment then available. The experience contributed to the Marine assessment that future amphibious operations should include a Seabee or comparable road-building component. The battalion was not fully assembled on Guam until 20 September, and one of its significant construction tasks was work connected with Harmon Airfield. On 17 August 1944, the battalion returned to Navy administration and was assigned to the 27th Naval Construction Regiment of the 5th Construction Brigade. It remained associated with other former Marine Corps construction battalions, including the 53rd. The wartime 25th NCB was decommissioned in November 1945, with the 133rd Naval Construction Battalion assuming its Guam work orders. The unit’s World War II lineage is notable because it served with Army, Navy, and Marine Corps formations. The battalion was recommissioned in October 1961 at Davisville, Rhode Island, within the Naval Construction Force Reserve. Its later homeports included Glenview, Illinois, and Fort McCoy, Wisconsin. From 1995 to 2014, Fort McCoy served as its homeport. The headquarters subsequently moved to Port Hueneme, California, where NMCB 25 remains identified as a Navy Reserve Seabee unit. Since reactivation, the battalion has supported overseas contingency operations and humanitarian missions. Recorded deployments include Iraq in 2006, Guantanamo Bay from 2009 to 2010, Haiti after the 2010 earthquake, Afghanistan in 2014, and Afghanistan in 2019. Its documented recognitions include Admiral Perry Awards in 1996, 2006, and 2019; a 2014 Citizens Patriot Unit Award; a Secretary of the Navy unit letter of commendation; and nine Navy 'E' awards listed for 1996, 1998, 2005, 2006, 2009, 2012, 2016, 2019, and 2020. The battalion also carries campaign recognition associated with World War II and later United States operations.
- 2014
Afghanistan deployment and unit recognition
[1]The unit’s documented modern record includes an Afghanistan deployment and a Citizens Patriot Unit Award in 2014.
- 1961
Battalion recommissioned as a reserve unit
[1]NMCB 25 was recommissioned in October at Davisville, Rhode Island, in the Naval Construction Force Reserve.
- 1945
World War II battalion decommissioned
[1]The wartime battalion was decommissioned in November after its Guam work orders were transferred to the 133rd Naval Construction Battalion.
- 1944
Guam assault and construction support
[1]NMCB 25 personnel landed under fire with the 3rd Marine Division and supported roads, logistics, artillery movement, and Harmon Airfield work.
- 1943
Bougainville deployment
[1]The battalion landed on Bougainville and provided construction and combat-support engineering alongside Marine formations.
- 1942
25th Naval Construction Battalion commissioned
[1]The battalion was commissioned on 13 September at Camp Bradford, Virginia, and moved to the Port Hueneme area.
Products and positioning
A reserve naval engineering and construction unit designed to provide expeditionary infrastructure, combat-support construction, and emergency response capabilities for United States Navy and joint-force missions.
Military engineering service
Expeditionary construction support
NMCB 25 provides trained Seabee personnel for deployed construction, repair, and infrastructure tasks. Its work can support bases, roads, airfields, utilities, and other facilities needed by naval, joint, or humanitarian operations. The battalion is an operational military unit rather than a commercial service provider.
Combat engineering · 1942
Combat engineering and shore-party support
The battalion’s World War II lineage includes shore-party and combat-support duties with Marine assault formations. Historically, its heavy construction equipment helped clear jungle, improve routes, move supplies, evacuate casualties, and prepare artillery positions during amphibious operations.
Emergency infrastructure support · 2010
Humanitarian and disaster-response construction
As a reserve Seabee unit, NMCB 25 can apply engineering and construction capabilities to emergency missions. Its recorded participation in Haiti after the 2010 earthquake illustrates the use of naval construction personnel in disaster-response environments.
Marketing campaigns
- 2010Haiti earthquake response
Haiti
NMCB 25 supported United States humanitarian operations after the Haiti earthquake with its construction and infrastructure capabilities.
Outcome. The mission extended the battalion’s reserve Seabee role beyond combat deployments into disaster assistance.
- 1944Guam campaign
Pacific theater
The battalion landed with the 3rd Marine Division and supported shore parties, road clearance, logistics movement, casualty evacuation, artillery emplacement, and airfield-related construction.
Outcome. Its work demonstrated the operational value of Seabee heavy equipment in amphibious operations and contributed to later recognition for the unit’s service.
- 1943Bougainville Campaign
Pacific theater
NMCB 25 landed and worked with other naval construction battalions in support of Marine operations on Bougainville, improving routes and infrastructure under combat conditions.
Outcome. The unit returned to Guadalcanal in early 1944 after completing its Bougainville assignment.
Brand decisions
1961
Reactivation in the Naval Construction Force ReserveStrategyBackground
After the World War II battalion was decommissioned, the Navy re-established the 25th unit lineage during the expansion and organization of the postwar reserve construction force.
Action taken
The battalion was recommissioned in October 1961 at Davisville, Rhode Island.
Aftermath
NMCB 25 continued as a Navy Reserve Seabee unit and later moved its homeport through Glenview and Fort McCoy before establishing its headquarters at Port Hueneme.
Recent events
- 2019
NMCB 25 deploys to Afghanistan[1]
Other
The unit conducted a recorded Afghanistan deployment as part of its modern expeditionary Seabee service.
- 2010
NMCB 25 contributes to Haiti earthquake response[1]
Other
The battalion supported United States relief operations following the Haiti earthquake, applying its construction and infrastructure capabilities to a humanitarian mission.
- 2006
NMCB 25 supports the Iraq operation[1]
Other
The reserve Seabee battalion deployed personnel for construction and engineering support in Iraq.
- 1961
NMCB 25 is recommissioned in the Naval Construction Force Reserve[1]
Other
The battalion was re-established at Davisville, Rhode Island, returning the 25th Naval Construction Battalion lineage to the Navy’s reserve construction force.
Sources2 sources
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