Royal Caribbean finalized a long negotiation by ordering a third ship in the 5,400-passenger Oasis class from the STX France shipyard.
The ship will be the same size as the Oasis and Allure of the Seas, and is intended for delivery in mid-2016.
Royal Caribbean had been negotiating with STX Finland, but financial support from the Finnish government apparently could not be worked out.
Royal Caribbean did not divulge the cost of the new ship. It said its capital spending for the next few years would be $1.3 billion in 2012, $700 million in 2013, $1.2 billion in 2014, $1.2 billion in 2015 and $1.3 billion in 2016, when the third Oasis ship is scheduled to be delivered.
When Royal Caribbean confirmed in November that it was negotiating for a third Oasis-class vessel, it said the price per berth would be less than the original two ships.
Royal Caribbean has a one-year option to build a fourth Oasis-class ship from STX France.
The contract with STX France includes the transfer of Pullmantur's Atlantic Star as part of the consideration. Follow Tom Stieghorst on Twitter @tstravelweekly.