USS Duluth (LPD-6), an Austin-class amphibious transport dock, was the second ship of the United States Navy named for the city in Minnesota.

Naval Base Subic Bay, Duluth participated in helicopter-centered Operation Bastion Hill near Cửa Việt (10 October – 1 November).

Underway for a WestPac cruise on 1 May 1970, Duluth loaded BLT 1st Battalion, 9th Marines at Okinawa for transfer to Subic Bay at the end of the month.

She then made several cargo lifts to Da Nang or to Yankee Station, delivering an H-3 helicopter to USS America, spare parts, and carried YFU-52 back to Subic Bay before steaming to United States Fleet Activities Sasebo, Japan, for rest and recreation 3–15 July.

In mid-October, Duluth embarked 140 Philippine marines for a joint exercise near Manila, but disaster recovery efforts in the wake of Typhoon Joan forced a cancellation of the operation.

The ship loaded elements of BLT 2nd Battalion, 4th Marines at Okinawa on 18 October before resuming Da Nang logistics support operations out of Subic Bay.

The LPD delivered vehicles, equipment and humanitarian supplies to Da Nang and embarked deck cargo and damaged PTFs for return to Subic.

On 1 April, following the outbreak of the North Vietnamese Easter Offensive, Duluth sailed to a holding station off South Vietnam to await developments.

[1] On 29 April, fourteen South Vietnamese, Marine and Air America helicopters landed delivering over 900 refugees to Duluth alone, including the Italian ambassador.

The Marines were also called upon to restore order and security around the Subic Naval Base after several "Sparrow teams" killed high ranking government officials in an attempted coup.

In late May after operations with the Australian Army and Navy, Duluth's port call in Mackay, Australia was cut short when the Amphibious Ready Group she was attached to was recalled "at best possible speed" across the Pacific to the evolving situation in Panama.

The ship remained in Singapore for six days before getting underway for the Indian Ocean and arriving off Mogadishu on 3 March to assist in the evacuation of American forces from Somalia.

Duluth then steamed off Kipini, Kenya, holding for possible contingency operations owing to the civil war in Rwanda, until 4 June when she sailed for Fremantle, Western Australia.

This plan, Operation Return Ox, set sail at 1730C from Bahrain on 23 July 1996 to intercept the motor vessel Ibn Tufail, a Pakistani ship on which it was believed Mughniyah was embarked.

While en route, the LPD stopped at Iwo Jima to launch amphibious vehicles in commemoration of the World War II battle.

While anchored at Guam on 28 December 2004, the LPD was ordered south for Operation Unified Assistance to aid victims of the devastating Indian Ocean tsunami.

Duluth arrived off Sri Lanka on 9 January 2005 and her crew and embarked Marines cleared helicopter landing zones, removed debris and helped clean up two devastated elementary schools.

The amphibious transport dock ship's last deployment ended in June 2005 after a six-month cruise to the Persian Gulf in support of Operation Iraqi Freedom.

Shortly after Duluth's final cruise, she was decommissioned at Naval Station San Diego in a ceremony on 28 September 2005 and LPD-6 was stripped from the national ship's registry.

A team of former crew members, including two former commanding officers, boarded the ship prior to scrapping for final photographs and collection of mementos.