From July through October 1955, Thomaston participated in the Arctic Resupply Project, provisioning stations on the Distant Early Warning Line before taking part in cold-weather landing exercises in the Aleutians in November 1955 and again in January and February 1956.

The landing ship's duties soon took her southward to the warmer climes of the Hawaiian Islands, where she conducted local operations and exercises in March and April.

Changing course, Thomaston found SS Barbara Fritchie in heavy seas, dead in the water, having lost a propeller and suffering rudder damage.

Departing San Diego on 10 January 1966 for WestPac, Thomaston arrived in Vietnamese coastal waters on 5 February and immediately commenced operations at Chu Lai and Da Nang, serving as boat haven at the latter port.

Relieved at Vũng Tàu by USS Point Defiance on 6 March, Thomaston sailed for repairs at Subic Bay, en route home via Hong Kong, Okinawa, Yokosuka, and Pearl Harbor.

After joining the Amphibious Ready Group off Vietnam in the I Corps zone, Thomaston commenced operations in support of marines of the Special Landing Forces (SLF) engaged ashore in the defense of Quảng Trị Province.

She spent the month of March steaming in coastwise logistics runs between Da Nang, Cam Ranh Bay and the burgeoning Army supply base at Wunder Beach.

Many small craft and pontoon piers serving the supply base received hull and machinery work by the crew in the ship's capacious well deck.

Later, on 2 June and again while in the vicinity of Valley Forge, Thomaston picked up men from the carrier who had jumped overboard to escape flames from a flight deck fire.

Thomaston next participated in Badger Catch III, the withdrawal of the Special Landing Force from the Cua Viet River area bordering on the extreme southern edge of the DMZ.

Following Exercise Hilltop XX in Subic Bay, Thomaston participated in Eager Yankee which landed elements of the SLF in Quảng Trị Province near Cua Tu Hien on 9 July before engaging, 13 days later, in Swift Play in the coastal area south of Da Nang.

On 2 March, Thomaston departed Subic Bay to execute Operation Eagle Pull which evacuated Americans and designated Cambodian citizens from the capital city of Phnom Penh.

She remained in readiness until the evening of 5 April, when Thomaston was ordered to Phú Quốc island to assist Vietnamese nationals evacuated from Da Nang.

She transferred food and medical supplies via her LCUs and LCM-8 assault craft to Vietnamese refugees quartered on Military Sealift Command (MSC) vessels.

The ship then headed on for the west coast of the United States, via Buckner Bay, Okinawa; and Pearl Harbor; and arrived at San Diego on 6 June 1975.

During USS Thomaston's 1981 Westpac as part of Amphibious Squadron Five, the ship and crew would receive a second Humanitarian Service Medal for the rescue of 77 Vietnamese refugees in the South China Sea in April 1981.

USS Thomaston was decommissioned 28 September 1984 and her name struck from the Naval Vessel Register 2 February 1992, and laid up in the National Defense Reserve Fleet, under temporary custody of the Maritime Administration (MARAD).

Permanent custody was reassigned to MARAD, 18 November 1998 for lay up in the National Defense Reserve Fleet, Suisun Bay, Benicia, California.

[1] Thomaston departed the Suisun Bay Reserve Fleet on 18 August 2011 to be cleaned by Allied Defense Recycling at the former Mare Island Naval Shipyard.