From December 11 the boat will depart from Can Tho, which is north of Soc Trang on the Hau River, touch Soc Trang on the coast, and head for the Con Dao archipelago in the East Sea.

The vessel can seat a maximum of 600 passengers, and tickets cost VND520,000 to VND990,000 ($22-43).

The largest twin-deck boat operating in the country was built by a shipyard of the Ministry of National Defense.

Named Trung Trac after a national heroine who ruled for three years after rebelling in AD 40 against the first Chinese domination of Vietnam, it is 47 meters long.

It will leave the Mekong Delta's hub Can Tho at 7:00 a.m. and sail back from Con Dao at 1:30 p.m. Each one-way trip will take around three and a half hours.

There are also speedboats to Con Dao from Ba Ria-Vung Tau, which borders HCMC.

Vietnam Air Services Company, a subsidiary of Vietnam Airlines, is the only airline to fly to Con Dao.

Budget carrier Vietjet Air is planning to begin services to Con Dao from Hanoi and HCMC. Newcomer Bamboo Airways has also expressed interest.

Last year Con Dao received more than 286,000 visitors, up 17.3 percent from 2017, including 32,000 foreign tourists.

Con Dao served as a jail for political prisoners for the French and later the U.S.-installed regime in Saigon. The old prison buildings still stand and are open to the public as a museum.

The island boasts pristine natural beauty with forested hills, sandy beaches and extensive coral reefs though it is now threatened by trash.