Built at a cost of US$1.4 billion by STX Europe, Oasis of the Seas is the first Oasis-class cruise ship to enter service. With a gross tonnage of 226,838 GT and spanning a length of 361.60 meters, she was the largest cruise ship at the time of service, surpassing the large Freedom-class cruise ships that are also in Royal Caribbean's fleet.

Oasis of the Seas can pack 5,484 passengers at double occupancy (up to 6,780 max) in her 2,742 rooms that spread across 16 passenger decks, complemented by a crew of 2,200.