3rd Battalion 3rd Marines (Trinity) 3rd Mar DIv. MCBH K-Bay

The 3rd Battalion, 3rd Marines (3/3), nicknamed “Trinity,” is an infantry battalion of the United States Marine Corps based at Marine Corps Base Hawaii, Kaneohe Bay (MCBH K-Bay), and is part of the 3rd Marine Division. Activated in 1942 during World War II, 3/3 participated in major Pacific campaigns, including Bougainville and Guam. The battalion saw significant action in Vietnam, Iraq, and Afghanistan, earning a reputation for effectiveness in counterinsurgency and expeditionary operations. Today, 3/3 continues to serve as a forward-deployed, rapid-response force, maintaining readiness for missions throughout the Indo-Pacific region.