About a third of the ship burned during its completion afloat in 1990, due to an accident involving some welding equipment.

This section was then rebuilt and the metal recycled to construct the next ship of the class, Majesty of the Seas.

[5] Prior to being retired from the Royal Caribbean International fleet, Monarch of the Seas (as she was then called) sailed to the Bahamas out of Port Canaveral, Florida.

[6][7] On 1 April 2013, after serving for Royal Caribbean International for 22 years, Monarch was transferred to Spain's Pullmantur Cruises, joining her sister ship MS Sovereign.

[10][11] In 2020, amid the COVID-19 pandemic, Monarch and MS Sovereign were placed into "cold lay-up" and Pullmantur Cruises filed for financial reorganization.

[18][19] The ship was drydocked for repairs for three months at Atlantic Marine's Mobile, Alabama, facilities.

The work also included replacement of machinery, 460 tons of shell plating, and 18 miles (29 km) of electrical wiring.

[20][21] Thirty-eight-year-old Captain Joern Rene Klausen was found dead in his stateroom aboard Monarch early the morning of January 30, 2006.

[23] On 14 March 2020, Panama repatriated 1,504 Colombian tourists from the cruise ship Monarch due to coronavirus fears.