To be named La Siesta, they will have a length of 110 meters and 55 luxury cabins each, and will be the largest vessels in the bay when completed.
They will also have a helipad.
Doan Manh Linh of the Department of Tourism of Quang Ninh Province, home to Ha Long, said currently there are no vessels with a helipad.
Belonging to inland waterway freight transport company Viet Thuan Group and Elegance Hospitality Group, the owner of La Siesta hotels and resorts, the ships are touted to offer a new travel experience.
Since its recognition as a UNESCO world heritage in 1994, Ha Long Bay has found a spot on the global tourism map, with travel bloggers and filmmakers gushing over its emerald waters and towering limestone pillars topped by rainforests.