The dock landing ship soon proceeded to Buckner Bay, Okinawa, and subsequently operated in Korean and Chinese waters, repairing small craft and serving in the mobile support unit attached to Amphibious Forces, Pacific Fleet.

Operating initially out of Jinsen (now Inchon), Korea, Tortuga subsequently conducted her support missions out of Tsingtao, Taku, and Shanghai, China; Hong Kong; and Yokosuka, Japan.

About this time, intelligence reports indicated that the Chinese Communists might take advantage of American preoccupation with the war in Korea by mounting an invasion, across the Taiwan Strait, of Nationalist-held Formosa.

Diverted to Haiphong from Yokosuka, Tortuga arrived at her destination on 21 August 1954 to take part in the massive evacuation of French nationals, in "Operation Passage to Freedom", as well as the moving of Vietnamese who chose not to live in the north.

The landing ship conducted four round trips from Haiphong in the north to Tourane (now Da Nang), Saigon, and Nha Trang in the south, before she returned to Yokosuka on 4 October.

In between deployments — which included exercises and equipment lifts and labors to help maintain the 7th Fleet's readiness — Tortuga conducted local operations put of west coast ports and underwent progressive modifications during regular availabilities.

For the remainder of the year 1964, Tortuga operated out of Yokosuka and conducted troop and equipment lifts between Japan and Okinawa until she headed home and arrived back at San Diego on 18 December.

Initially, Tortuga operated in the Rung Sat Special Zone between Saigon and Vung Tau, helping to guard the entrance to the shipping channels snaking through Viet Cong (VC) territory to the capital city.

Tortuga shifted to the Mekong Delta region on 12 June to serve as a floating base for the Navy's fast PBR's of Task Force 116 and for a detachment of Army Bell UH-1B Huey helicopter gunships.

During her support operations with the riverine assault groups, Tortuga received a number of distinguished visitors ranging from General William C. Westmoreland, Commander, Military Assistance Group; Rear Admiral Norvell G. Ward, Commander, Naval Forces Vietnam; as well as United States Ambassador to South Vietnam Henry Cabot Lodge; and news commentator Chet Huntley, who brought with him an NBC camera team to record a news story on Tortuga's river-patrol base activities.

Following a period of refresher training and amphibious exercises, Tortuga sailed on 21 July 1967 from San Diego and arrived, via Hawaii, Guam, and the Philippines, at Da Nang on 5 September.

On 17 February, while en route to Yokosuka, Tortuga conducted her first underway refueling — with USS Cook receiving 31,000 gallons of Navy Special Fuel Oil (NSFO).

Underway on 11 March with her special cargo, the landing ship soon reached Subic Bay, unloaded, and proceeded for Kaohsiung, Taiwan, en route to South Vietnam.

Meanwhile, one boat crew, composed of one officer and five enlisted men, armed with rifles and Thompson submachine guns, kept a constant vigil in an LCVP which circled the ship at a distance of 60-70 yards.

Reaching Subic Bay after an uneventful passage, the ship unloaded the explosives and soon received orders to transport a much-needed suction dredge up the Saigon River to Nhà Bè Base, through territory largely controlled by the VC.

In July, Tortuga transported the first increment of Marines and their equipment for Operation Keystone Eagle, from Cửa Việt Base, South Vietnam, to White Beach, Okinawa, before returning up the Saigon River to Nha Be with a load of palletized cargo.

Subsequently supporting Operation Sea Float, delivering two pontoons and 32 pallets of ammunition from Nhà Bè to Tân Mỹ Base, Tortuga onloaded men and equipment from "Charlie" Battery, 1st Light Antiaircraft Missile Battalion (LAAM), 1st Marine Aircraft Wing, at Da Nang harbor for transport to the west coast of the United States.