Torstein Hagen's Viking Ocean Cruises has signed up for two more cruiseships at Fincantieri in Italy.
The vessels come with options for two additional units and will be delivered in 2021 and 2022.
Fincantieri said they are sisters to the six already ordered at the yard.
Final contracts will become effective when financing is fixed.
Each ship is 47,800 gt and accommodates 930 people in 465 cabins.