3d Assault Amphibian Battalion
3d AA Bn Logo
1st Marine Division
Camp Pendleton, California

The mission of 3d AA Bn is to land the surface assault element of the landing force and their equipment in a single lift from assault shipping during amphibious operations to inland objectives; to conduct mechanized operations and related combat support in subsequent operations ashore.

3D Assault Amphibian Battalion was originally activated 16 September 1942 at San Diego, California, as 3D Amphibian Tractor (Amtrac) Battalion and assigned to the 3D Marine Division. During December 1942, the battalion relocated from San Diego a short distance up the coast to Camp Pendleton. After training for a few months, the battalion then deployed in February-March 1943 to Auckland, New Zealand in preparation for combat in the Pacific theater.

During World War II, the battalion was primarily armed with Landing Vehicle Tracked (LVT), specifically the LVT-2 also known as "WATER BUFFALOS." The battalion fought in the following combat actions:
- Bougainville with 124 LVT-1s
- Guam with 193 LVT-2s and LVT-4s
- Iwo Jima with 90 LVT-2s

For its actions in World War II 3D Amphibian Tractor Battalion was awarded the Presidential Unit Citation Streamer, Asiatic-Pacific Campaign Medal Streamer With Four Bronze Stars, and the World War II Victory Medal Streamer.

At the conclusion of World War II the battalion redeployed in March 1945 to Maui, territory of Hawaii and then relocated during February 1946 back to Camp Pendleton, California. It was deactiviated several months later on 1 May, 1946.

1952 - 1966

3D Amphibian Tractor Battalion was reactivated 1 April, 1952 at Camp Pendleton, California and assigned to Fleet Marine Force Pacific. It was subsequently reassigned during October 1955 to the 1st Marine Division Elements where it participated in the Cuban Missile Crisis October-December 1962.

During this period, the battalion was still armed with LVTs - transitioning primarily to the LVT-5 in the late 1950s.


3D Amphibian Tractor Battalion deployed during February 1966 to Camp Schwab, Okinawa and redeployed again in March 1966 to the Republic of Vietnam. There, the battalion fought in the Vietnam War from March 1966 - January 1970. During this conflict, the battalion distinguished itself at Chu Lai, Da Nang, An Hoa, Hoi An

Throughout Vietnam, the battalion was armed with variants of the LVT-5.

For its actions in Vietnam, 3D Amtrac Battalion was awarded the Presidential Unit Citation Streamer, Navy Meritorious Unit Commendation Streamer, National Defense Service Medal Streamer,Vietnam Service Medal Streamer With Two Silver Stars, Vietnam Gallantry Cross with Palm Streamer, and the Vietnam Civil Actions Medal Unit Citation Streamer.

The battalion relocated during February 1970 to Camp Pendleton, California, and was reassigned to the 5th Marine Expeditionary Brigade. It was again reassigned in August 1970 to the 5th Marine Amphibious Brigade. Subsequently, in April 1971, the battalion was reassigned to the 1st Marine Division with whom it remains to this day. In the early 1970s the battalion transitioned from the LVT-5 to its replacement the LVT-7.

On 30 December 1976, the battalion was re-designated from 3D Amphibian Tractor Battalion to 3D Assault Amphibian Battalion (written as 3D AABn). The battalion participated in numerous training exercises throughout the remainder of the 1970s.


Throughout the 1980s, 3D Assault Amphibian Battalion deployed companies on its regular schedule of six month deployments to the forward units in Hawaii and Okinawa, including units aboard amphibious troop ships for fast-reaction forces in the Pacific and Indian Oceans and into the Persian Gulf. It shared personnel and vehicles with the 1st Armored Assault Battalion as part of the Unit Deployment Program.

In the early 1980s the battalion's LVT-7s underwent a Service Life Extension Program (SLEP), which converted the LVT-7 vehicles to the improved Amphibious Assault Vehicle-7A1 (AAV-7A1) by adding an upgraded engine, transmission, and weapons system improving the overall maintainability of the vehicle.

Realizing the need to mechanize units participating in the Combined Arms Exercises (CAX), two platoons of AAVs were transferred to the Marine Corps Air Ground Combat Center Twentynine Palms (MCAGCC) in July of 1979. The two platoons were formed from Camp Pendleton -- one went to Company A, 3D Tank Battalion, and the other platoon went to Company B, 3D Tank Battalion.

The two platoons later merged and became Company D, 3D Tank Battalion, in September 1980. Two additional platoons from 3D Assault Amphibian Battalion in Hawaii arrived onboard the Marine Corps Air Ground Combat Center in December 1981. A redesignation ceremony was held on 18 January 1982 in which the colors of Company D, 3D Tank Battalion were formally retired and replaced with the new colors of Company D (Rein), 3D Assault Amphibian Battalion. The company was instrumental in training Marines in desert warfare as they rotated in and out of the live-fire desert training area, a key to the Marine Corp's success in the 1991 Gulf War.

For its superior performance from 1983 - 1985, the battalion was awarded a Navy Meritorious Unit Commendation.


In August 1990, 3D Assault Amphibian Battalion received orders to prepare for an overseas deployment to Southwest Asia as a response to the Iraqi invasion of Kuwait. In the following month the unit deployed to Saudi Arabia and received shipments of its Amphibious Assault Vehicles from Maritime Prepositioning ships to augment its current vehicle ranks.

During this time, the battalion began upgrading its P-7A1s to carry the UGWS (UpGunned Weapons Station), which mounts a .50 cal (12.7mm) M2HB machine gun and a Mk-19 40mm grenade launcher.

In preparation for the assault into Kuwait, the battalion divided into two main mechanized infantry task forces, along with 1st and 3D Tank Battalions, to form Task Force Ripper and Task Force Papa Bear respectively. The units trained and patrolled the Saudi frontier with Kuwait until the start of the ground war in February 1991. After five days of combat, the two task forces, along with other other Marine task forces, British and Pan-Arab units, captured Kuwait International Airport and a cease-fire was announced. During the march to Kuwait City, the mechanized infantry task forces were responsible for the defeat of numerous Iraqi regiments, the capture of tens of thousands of Iraqi prisoners, and the capture or destruction of thousands of enemy armored vehicles. 3D Assault Amphibian Battalion returned to Camp Pendleton in March 1991.

For its actions during the Gulf War, the Battalion was awarded a Navy Unit Commendation Streamer, National Defense Service Medal Streamer, and the Southwest Asia Service Medal Streamer With Two Bronze Stars.


On 9 December 1992, in support of Operation Restore Hope, elements of 3D Assault Amphibian Battalion attached to the 15th Marine Expeditionary Unit landed on the beach just outside the Mogadishu International Airport in Somalia. These initial forces were soon followed by Bravo, Delta, and Headquarters and Service Companies of 3D Assault Amphibian Battalion. These units' operations stretched from Mogadishu to Bardera, Baidoa, and Kismayo. The battalion served as a blocking force for the International Airport's reception of airlifted humanitarian supplies, then extended its services as road guards for supply convoys and foot patrols in and around Mogadishu.

Elements of 3D Assault Amphibian Battalion served in Somalia or off the coast aboard MEUs from 1992 until approximately 1995. For its actions during Operation Restore

Hope, the battalion was awarded the Joint Meritorious Unit Award Streamer and the Armed Forces Expeditionary Medal Streamer.


In 2003, 3D Assault Amphibian Battalion participated in Operation Iraqi Freedom as part of the 1st Marine Division. They first deployed in February of 2003 to Kuwait and crossed the border into Iraq in March, attacking all the way to Baghdad. The battalion served as the primary mechanized assault support for the infantry and proved to be an invaluable asset in crossing the vast distances and urban areas of Iraq. The battalion continues to support operations throughout the world.

The battalion's actions in support of the Global War on Terror have earned it a Presidential Unit Citation Streamer, Navy Meritorious Unit Commendation Streamer, National Defense Service Medal Streamer, Global War on Terrorism Expeditionary Medal Streamer, and the Global War on Terrorism Service Medal Streamer.

1942 - 1946:

Activated 16 September 1942 at San Diego, California, as 3rd Amphibian Tractor Battalion and assigned to the 3rd Marine Division

Relocated during December 1942 to Camp Pendleton, California

Deployed during February-March 1943 to Auckland, New Zealand

Participated in the following World War II campaigns:
Iwo Jima

Redeployed during March 1945 to Maui, territory of Hawaii

Relocated during February 1946 to Camp Pendleton, California

Deactiviated 1 May 1946

1952 - 1975:

Reactivated 1 April 1952 at Camp Pendleton, California, and assigned to Fleet Marine Force, Pacific

Reassigned during October 1955 to the 1st Marine Division

Element participated in the Cuban Missile Crisis, October-December 1962

Deployed during February 1966 to Camp Schwab, Okinawa

Redeployed during March 1966 to the Republic of Vietnam

Participated in the war in Vietnam, March 1966 - January 1970, operating from:
Chu Lai
Da Nang
An Hoa
Hoi An

Relocated during February 1970 to Camp Pendleton, California, and reassigned to the 5th Marine Expeditionary Brigade

Reassigned during August 1970 to the 5th Marine Amphibious Brigade

Reassigned during April 1971 to the 1st Marine Division


Redesignated 30 December 1976 as 3D Assault Amphibian Battalion

Participated in numerous training excercises throughout the 1970's - 1980's

Participated in Operations Desert Shield and Desert Storm, Southwest Asia, August 1990 - March 1991

Participated in Operations in Somalia, December 1992 - April 1993, January - March 1995

Deployed during January 2003 to Kuwait in support of Operation Enduring Freedom

Participated in Operation Iraqi Freedom, Iraq, March-May 2003

Elements participated in Operation Iraqi Freedom, Iraq, March-October 2004

Contact the 3D Assault Amphibian Battalion Embedded MFLC at 760-573-0354

Please leave a voicemail to schedule an Appointment


Military & Family Life Counseling Program


Military families face unique challenges. They may struggle with issues such as deployment-related stress, reintegration and pressures of managing parenting and finances while a loved one is deployed.

To support military families facing these or additional challenges, the Military and Family Life Counseling Program:

·       Provides short-term, non-medical counseling services to service members and their families at no cost

·       Provides psycho-education to help military service members and their families understand the impact of deployments, family reunions following deployments and other stresses related to military life

·       Augments existing military support services

·       Offers flexible service delivery

·       Can provide services on or off of military installations

·       Can provide services to individuals, couples, families and groups


With the exception of child abuse, domestic abuse and duty to warn situations services are private and confidential.


About Military and Family Life Counselors

·       Masters or Doctorate-level licensed counselors

·       Work with families, individuals, couples and children

·       Work with existing military and family support programs to complement services provided

Non-Medical Counseling Services

Life skills

·       Anger Management

·       Communication

·       Relations Issues

·       Productivity at work

·       Decision-making Skills

·       Conflict Resolution

·       Parenting

Military Lifestyle

·       Deployment Stress

·       Reintegration

·       Coping Skills

·       Separation

·       Homesickness                         

·        Building

·       Resiliency

·       Relocation  adjustment    

·       Sadness, Grief & Loss




Service Providers and Leaders

Military and Family Life Counseling services are available at installation Military and Family Support Centers.

If an installation is not nearby, military service providers and leaders can request non-medical counseling services for unit events at: https://supportrequest.militaryonesource.mil


Contact the 3D Assault Amphibian Battalion Embedded MFLC at 760-573-0354

Please leave a voicemail to schedule an Appointment


3rd Amphibious Assault Chaplain





Contact the Chaplain directly:
 Camp Pendleton:
Cell: (314) 800-8859
(760) 725-2005


LT. Costephens is a native of St. Louis, Missouri.  He earned his bachelor’s degree in Christian Ministry at Missouri Baptist College in 2001 while concurrently serving as the Minister of Students at First Baptist Church of Godfrey in Godfrey, IL.  He then graduated from Southern Baptist Theological Seminary in December of 2007 with a Master of Divinity in Christian Ministry.  He served as Minister of Youth at St. John UMC in Prospect, KY while in seminary.  He was commissioned as an active-duty chaplain in September of 2019.

Chaplain Costephens began his Navy service in January 2020 as he reported to Officer Development School.  He successfully graduated on February 28, 2020.  His education has been furthered for Navy service at Naval Chaplaincy School and Center.  He graduated on April 22, 2020.  Currently Chaplain Costephens is serving as chaplain for 1st Marine 3rd Amphibious Assault Battalion. 

Prior to his commissioning, Chaplain Costephens served as the Senior Pastor of First Baptist Church of Ferguson, MO.  The goal of this pastorate was to combine a new church start with an established church with a rich history.  Over the course of four years, from 2015 to 2019, the churches merged, changed leadership structure, and grew in key areas of membership.  He became familiar with helping those in physical and monetary need. He also further developed his ability to counsel those with spiritual, emotional, and mental distress.  Before that he led a church start up entitled Passage Church from 2009-2015.  He was instrumental in growing the church and having it become a positive impact on the community.  Under his leadership, home improvement programs were started, children’s needs were met, and those with extreme needs of hunger were assisted. 

Leticia “Missy” Harrison

Office: 760-725-2316

Cell Phone: 760-840-7381

Deployment Readiness Coordinator/ 3d Assault Amphibian Battalion

     Mrs Harrison began her affiliation with the Marine Corps upon her marriage to a Marine in 1996. Her career in support of Marine families started soon after by becoming a Key Volunteer for the Inspector-Instructor Staff, 4th Reconnaissance Battalion in San Antonio, Texas. Upon completion of that tour and a subsequent one-year move to Quantico, Virginia, in 1999 Mrs Harrison became the Key Volunteer Coordinator for 3rd Battalion, 7th Marines at the Marine Air Ground Combat Center in Twentynine Palms, California. Initially working for LtCol Drew Bennet and then for LtCol Kip Haskell, she facilitated the flow of information from the battalion to dependent spouses, recruited and supervised the training for volunteers, organized pre-deployment briefs for families and coordinated social events including family days and Jayne Wayne days. In 2001, she was recognized as the Key Volunteer of the Year for the Western Region of the United States. 


     In 2005, after accompanying her husband for a three-year joint duty assignment in El Paso, Texas, Mrs Harrison resumed the role of Key Volunteer Coordinator this time in support of Col Peter Petronzio and the Marine Special Operations Advisor Group (MSOAG), Marine Corps Forces Special Operations Command at Camp Lejeune, North Carolina. This unit is now known as 3rd Marine Raider Battalion. MSOAG was a brand-new unit and Mrs Harrison was the first KVC, successfully establishing the KV program and recruiting volunteer assistants.


     When the Marine Corps began the paid civilian Family Readiness Officer program in 2008, Mrs Harrison was one of the first Family Readiness Officers hired by Marine Corps Community Services. Her first tour as a Family Readiness Officer was with 2nd Reconnaissance Battalion, 2nd Marine Division under LtCol Larry Landon. Again she was charged with establishing a program where none had existed before and did so successfully while supporting family members through multiple MEU and OIF deployments.


      Mrs Harrison moved with her family to Southern California in 2010 and resumed duties as a Family Readiness Officer with Marine Aviation Logistics Squadron-16, Marine Aircraft Group-16, 3rd Marine Aircraft Wing at Marine Corps Air Station Miramar. Working in support of LtCol James Carroll, she supported families throughout the squadron’s OEF deployment and coordinated multiple homecoming and reintegration events upon redeployment in 2011.


      In July, 2011, Mrs Harrison was requested by-name by LtCol Brian Bruggeman to transfer to 1st ANGLICO in order to replace his previous FRO. Again, she stepped into a unit’s FRO position in the middle of its OEF deployment, established supportive relationships with the unit’s families and facilitated Marines’ and sailors’ reintegration with their families upon redeployment. Mrs Harrison remained at 1st ANGLICO four more years, earning MCCS’s Five-year Service award in 2013 and supporting family readiness throughout subsequent combat deployments. 

She moved to her current position at 3d AABn in October of 2021


OOD: (760) 725-2005

Sergeant Major: (760)763-5058

FRO (760) 725-2316

MFLC (760) 573-0354

SACO: (760) 763-2271

S-1: (760) 763-5052

S-2: (760) 725-8883

S-3: (760) 725-2881/2440

S-4: (760) 725-2447/2744

S-6: (760) 725-2878

S-6: (Helpdesk) (760) 725-7053

Camp Pendleton Directory Assistance:  760-725-4111

Mailing Address:
3D Assault Amphibian Battalion
1st Marine Division (REIN)
P.O. Box 555574 
Camp Pendleton, CA 92055-5574

            3D AABN 

24/7 Support Line (760) 500-1707

DOD SAFE Hotline (877) 995-5247







3d Assault Amphibian Battalion Leaders

Commanding Officer, 3d Assault Amphibian Battalion

LtCol D. R. Petronzio

LtCol Petronzio attended Officer Candidate school through the NROTC program after graduating from theVirgina Military Institute in May 2006....

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Official Photo

Sergeant Major, 3d Assault Amphibian Battalion

SgtMaj A. C. Gay

Sergeant Major Gay enlisted into the Marine Corps in the Delayed Entry Program on 16 December 1999. He reported to Marine CorpsRecruit Depot San Diego, California in July 2000 for recruit training....

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Official Photo

1st Marine Division