With the buildup of United States and other Free World Military Forces in South Vietnam, the Vietcong developed teams of sappers and swimmers to conduct clandestine attacks against riverine traffic, harbor anchorages and coastal cities and towns.

[2]: 13–4 The plans provided for a harbor defense unit at each location with the mission of detecting and defending assigned land areas, water areas and water approaches against small surface craft attack, intrusion by deception craft, sabotage by sneak attack, underwater swimmers or subversive personnel and enemy mine-laying operations.

In phase 1 Mobile Inshore Undersea Warfare Surveillance (MIUWS) units consisting of five officers and 54 enlisted men would be deployed to each of the sites.

[5] With the arrival of 16 Boston Whaler skimmer crew personnel on 1 December Stable Door forces in South Vietnam reached a total of 496 men.

Construction was started on two quonset huts for a galley and mess hall and a potable 'water system was installed at the Cam Ranh Bay harbour defense base.

At Vung Tau construction was started on four barracks and plans were drawn for the erection of a quonset hut for administrative and recreation spaces.

[9] At 02:50 on 31 January 1968 a Cam Ranh Bay a Stable Door patrol succeeded in surfacing an enemy swimmer through the use of routine offensive grenade drops in the vicinity of the Norwegian tanker SS Pelican.

Approximately 30 minutes later, while the captured swimmer was being questioned, an explosion occurred on the bow of the SS Pelican, causing moderate damage.

[10]: 19 Also during January 1968 one officer and five enlisted men arrived at Vũng Rô Bay to conduct advance plarming and liaison with local U. S. Army commands in preparation for establishing a Stable Door unit there.

[11]: 25 On 15 June 1970 the Qui Nhon Stable Door Unit was turned over to Republic of Vietnam Navy (RVNN) Harbor Defense control.

[15] In late 1966 the Royal Australian Navy (RAN) formed Clearance Diving Team 3 comprising one officer and five sailors and they arrived in Saigon in February 1967 before moving to Vung Tau.

In August 1970 the team moved to Camp Tien Sha in Danang and assumed responsibility for naval EOD disposal across I Corps.

[1] Inshore Undersea Warfare Group One units protected approximately 17,000 ships per year of which over 10,000 were checked by Stable Door EOD Teams.