Viking has signed contracts for two new cruise ships and agreed options for a further four.
The two 998-passenger ocean cruise vessels are due to be delivered in 2030.
The value of the agreement, subject to financing and other terms and conditions, was described as “large” but undisclosed.
The additional ships would enter service in 2031 and 2032.
The 54,300 ton vessels are identical to Vikings current ‘small ship’ fleet.
Italian ship builder Fincantieri said the new ships would be built “according to the latest environmental rules and navigation regulations”.
The deal follows a relationship between the line and the ship builder dating back to 2012 involving 22 ships.
Fincantieri chief executive Pierroberto Folgiero said: “This new order represents another step forward in our collaboration with Viking.
“This agreement not only strengthens our order book but it ensures further depth of work in our shipyards over the long term, positioning us at the forefront of driving the industry towards energy transition.”