[7][8] Construction of the ship took 30 months, which included the steel cutting in March 2015, the keel laying in April 2016, and the sea trials in November 2017.

[9] Carnival Horizon embarked on her maiden voyage on April 2, 2018 from Barcelona for a 13-day Mediterranean sailing, visiting ports of call in Italy, Croatia, Greece, and Malta.

[13] The ship continued a series of cruises for a short season in the Mediterranean before re-positioning to New York City in May for the remainder of summer 2018.

[16] On November 15, 2019, a passenger fell four stories off a balcony to his death from a lower deck of the ship just as it was returning to Miami, Florida.

According to the medical examiner's office, it was revealed that the passenger's death was due to blunt force trauma and not a suicide.