Naval Mobile Construction Battalion Four
NMCB-4 "Fabulous Four"
The distinguished history of Naval Mobile Construction Battalion (NMCB) 4 began with its commissioning on May 11, 1942. The original battalion consisted of approximately 32 officers and 1,073 enlisted personnel, with an average age of 37. During World War II, the battalion was initially deployed to the harsh Arctic conditions of Alaska and the Aleutian Islands, where they constructed advance bases under persistent Japanese aerial bombardment. Due to the extreme cold weather operations in this austere environment, the battalion earned the nickname “The Penguin Battalion,” a moniker that reflects both their operating conditions and resilience in one of the most challenging climates faced by Seabees.
By 1943, the battalion expanded operations into the Pacific, supporting base construction efforts on Guam. Advance elements landed on D+6, with the main body arriving, August 30, 1944.. In 1945, the battalion relocated to Okinawa, Japan, where they constructed roads, camps and a major ship repair facility at Baten-Ko, Okinawa while also conducting recovery operations following the destructive typhoon on October 9, 1945. Following the conclusion of World War II, the battalion was decommissioned as part of post-war demobilization.
With the outbreak of the Korean War, the Navy reactivated the unit under its modern designation. On February 12, 1951, orders were issued to establish NMCB-4 at Norfolk, Virginia, with its commissioning occurring on March 9, 1951. The battalion deployed globally throughout the 1950s, operating from homeports including Davisville, Rhode Island, and supporting missions in Bermuda, Morocco, Italy, Cuba, Trinidad, Ecuador, Newfoundland, Puerto Rico, Scotland and Spain.
In 1962, the battalion supported defensive operations at Naval Station Guantanamo Bay during the Cuban Missile Crisis, reinforcing base security amid heightened tensions with the Fidel Castro regime. This effort - referred to in Seabee histories as Project Might - involved the rapid construction of extensive defensive works, significantly strengthening the installation’s defensive posture. In November 1965, NMCB-4 transferred permanently to Port Hueneme, California, marking its transition to West Coast operations.
During the Vietnam War, NMCB-4 completed four deployments, conducting critical construction operations in Chu Lai, Da Nang, Quang Tri, and Phu Bai, Vietnam. Their efforts included runway repair, airfield construction, fuel pipeline installation and large-scale base development. Notably, the battalion constructed extensive infrastructure along Highway 1 and supported Marine and Army operations through the rapid development of expeditionary facilities.
In the 1970s, the battalion continued global operations, including significant contributions to Operation New Life in Guam, where they constructed over 3,800 facilities for Vietnamese refugees. In 1979, they responded to Typhoon Tip in Japan, rebuilding Marine Corps barracks at Camp Fuji and restoring critical communications infrastructure.
Throughout the 1980s, NMCB-4 expanded its operational footprint across the Middle East, Pacific and Europe, supporting contingency construction and joint exercises such as Team Spirt in the Republic of Korea. During Operation Desert Shield in 1990, the battalion deployed to Saudi Arabia, where they constructed a 2,000-person camp, taxiways and support infrastructure for coalition forces.
In 1991, following the eruption of Mount Pinatubo, the battalion deployed to Subic Bay in the Philippines to conduct large-scale disaster recovery operations, including debris removal, infrastructure restoration and emergency construction. In 1992, they supported Hurricane Andrew relief efforts in Florida, executing one of the largest Seabee airlift operations in history.
In 1994, NMCB-4 contributed to Operation Sea Signal at Guantanamo Bay, Cuba, constructing facilities capable of housing nearly 20,000 migrants as part of a joint-service humanitarian effort.
Entering the 21st century, the battalion supported operations in the Global War on Terror. Deployments included Operation Enduring Freedom in the Philippines (2002) and Operation Iraqi Freedom (2003), where NMCB-4 provided critical construction and mobility support, including operations in Baghdad.
From 2007 through 2013, the battalion maintained a high operational tempo, supporting missions across Iraq, Afghanistan and multiple global locations, while also executing humanitarian assistance and engineering support missions across several continents. In 2014, NMCB-4 earned its third consecutive “Best of Type” award, highlighting sustained excellence in operational performance.
In recent years, the battalion has continued to play a critical role in supporting Indo-Pacific operations and advancing regional stability. From November 2023 to June 2024, NMCB-4 deployed to the U.S. Indo-Pacific Command area of responsibility, where it executed a wide range of construction operations, supported fleet commanders, and participated in Theater Security Cooperation initiatives designed to strengthen alliances and improve partner nation capabilities. During the deployment, the battalion provided expeditionary engineering support for contingency operations, horizontal and vertical construction projects, camp sustainment and facility improvements across multiple locations in the theater.
In 2024, NMCB-4 supported major multinational exercises such as Keen Edge and Pacific Partnership, demonstrating the Navy Seabees’ ability to rapidly deploy and operate in austere environments while integrating with joint and allied forces. Detachments operated in Timor-Leste, Palau and Papua New Guinea, where they completed projects including road improvements, public facility renovations, utilities upgrades and site preparation efforts that directly enhanced regional infrastructure and disaster response readiness. These efforts improved operational access for U.S. and partner forces while delivering lasting benefits to local communities.
In addition to construction missions, the battalion conducted subject matter expert exchanges and training events with partner nation militaries and civilian agencies, sharing expertise in expeditionary engineering, construction management, and humanitarian assistance planning. Through these engagements, NMCB-4 strengthened interoperability, built enduring relationships and reinforced the U.S. commitment to a free and open Indo-Pacific. The deployment further highlighted the battalion’s readiness, adaptability and legacy of providing combat engineering excellence and humanitarian support wherever needed.
NMCB-4 has earned the “Best of Type” designation eighteen times and received numerous awards, including five Peltier Awards, the Presidential Unit Citation, multiple Navy Unit Commendations, and the Navy Meritorious Unit Commendation.
From its origins in the Aleutian Islands to its modern operations across the Indo-Pacific, NMCB-4 continues to exemplify the Seabee “Can Do” ethos - delivering expeditionary engineering excellence, enabling operational readiness and strengthening global partnerships. |