To be home ported at Long Beach, the destroyer returned to the United States in June 1964.
On 20 August 1965 Mansfield again sailed westward for duty with the 7th Fleet.
For the next 6 months she carried out screening and plane guard duties with fast carriers, and provided gunfire support for South Vietnamese, Australian, and American forces fighting in South Vietnam.

In June 1966, Mansfield was once again assigned Yokosuka Naval Base as her homeport, after which her deployment schedule repeatedly took her back to the South China Sea for operations off the coast of Vietnam.
Excluding 2 weeks in September with TF 130 as an alternate recovery ship for Gemini XI and 2 weeks in late November as station ship at Hong Kong, she spent the remainder of 1966 off the Vietnamese coast in roles which ranged from blockade patrol in the I Corps area and the interdiction of junk and sampan traffic from the north into South Vietnam, to gunfire support south of Saigon.
Adding air‑sea rescue to her services in 1967, she has continued to carry out similar missions in support of Allied operations in Vietnam from 1967 into 1970.
On September 25, 1967, 0930,the Mansfield was hit by North Vietnam shore battery off Tiger Island, north of the DMZ.
MM2 Richard Archer was KIA and 19 were wounded.
To be home ported at Long Beach, the destroyer returned to the United States in June 1964. On 20 August 1965 Mansfield again sailed westward for duty with the 7th Fleet. For the next 6 months she carried out screening and plane guard duties with fast carriers, and provided gunfire support for South Vietnamese, Australian, and American forces fighting in South Vietnam.
In June 1966, Mansfield was once again assigned Yokosuka Naval Base as her homeport, after which her deployment schedule repeatedly took her back to the South China Sea for operations off the coast of Vietnam. Excluding 2 weeks in September with TF 130 as an alternate recovery ship for Gemini XI and 2 weeks in late November as station ship at Hong Kong, she spent the remainder of 1966 off the Vietnamese coast in roles which ranged from blockade patrol in the I Corps area and the interdiction of junk and sampan traffic from the north into South Vietnam, to gunfire support south of Saigon. Adding air‑sea rescue to her services in 1967, she has continued to carry out similar missions in support of Allied operations in Vietnam from 1967 into 1970. On September 25, 1967, 0930,the Mansfield was hit by North Vietnam shore battery off Tiger Island, north of the DMZ. MM2 Richard Archer was KIA and 19 were wounded.
USS Mansfield