The eight new ships are scheduled for delivery by 2030 and will grow Ama's fleet to more than 40. Chief executive Catherine Powell said the order was a "direct response to strong demand from guests".
"These new ships represent exciting opportunities for our valued travel partners and us to grow together," said Powell. The line added it will continue to work close with the trade to make its product available to their clients.
Further details of the new ships will follow "in the months ahead".