[8] She was built in 2018 in the Chantiers de l'Atlantique shipyard in Saint-Nazaire, France,[9] the fourth in Royal Caribbean's Oasis class of cruise ships.

[12] Symphony of the Seas is about 30 metres (98 ft) longer than the largest military ships ever built, the U.S. Nimitz-class aircraft carriers.

[20] One of the key design features is the use of only LED or fluorescent lights in order to avoid the heat generation from incandescent bulbs, thereby reducing the load on air conditioning systems.

[25] From 15 to 18 February 2018, the cruise ship underwent sea trials[26] and was formally turned over to Royal Caribbean International on 23 March.

[29] On 31 March 2018, Symphony of the Seas offered her first passenger cruise[5] and began her maiden voyage on 7 April for a week-long trip through the Mediterranean.

[36] In 2020, Channel 4 in the United Kingdom aired a behind-the-scenes show featuring Symphony of the Seas called Billion Pound Cruise.