Construction Battalion Maintenance Units originated during World War II when 136 units were established. During the Vietnam Conflict two units were activated, CBMU 301 and 302. Following Vietnam, CBMU 302 was retained and during recent realignment CBMU 202 and 303 were formed.
CBMU 303 was commissioned on August 21, 1993 at U.S. Naval Station Treasure Island, San Francisco, CA. The unit was formed from components of Public Works Center Guam, Subic Bay, Yokosuka/Pearl Harbor, Naval Mobile Construction Battalions TWO, SIXTEEN and EIGHTEEN. CBMU 303 was initially headquartered at Treasure Island with four detachments located in San Diego, Treasure Island, Bremerton Washington and Honolulu Hawaii. In September 1994, the Headquarters was relocated to San Diego, California and detachment were realigned to San Diego, Alameda, California, Moreno Valley, California and Honolulu, Hawaii.
Although CBMU 303 is a relatively young command its personnel were consolidated from predecessor commands which have a history in support of the one Navy concept. With the call-up of PWC Subic Bay, elements of PWC Yokosuka and NMCB 16, the reserve CBMU mission was exercised and accomplished. Approximately one third of CBMU 303's members were activated to either support the civilian strike at Subic Bay and then continued on to Southwest Asia at various sited in Saudi Arabia, Bahrain, Qtar and Kuwait, or to relieve NMCB 4 from Roosevelt Roads, Puerto Rico so NMCB 4 could be deployed to Saudi Arabia.
In addition to its involvement during Desert Shield/Desert Storm, CBMU 303 has also distinguished itself in Seabee history by creating the Marvin Shields Memorial, located in Gardiner, Washington, for the only Seabee to be awarded the Medal of Honor. Other projects include building restorations/modifications, power supply at the Navy's Survival Training Site, pre-engineered buildings and virtually all other aspects typically associated with CBMU's.