An alert was issued around 02:00 BST for a search operation north of Les Casquets rocks, west of Alderney. The French search and rescue service reported that the woman was airlifted from the sea by a helicopter crew but was later pronounced dead by medical personnel.
According to a passenger onboard, alarms rang three times, signaling that someone had gone overboard. The passenger, who wished to remain anonymous, said: "About half an hour later, the cruise director informed us that they were searching for a missing passenger, which would delay our arrival in Southampton."
In a statement, MSC Cruises confirmed: "A guest on board MSC Virtuosa went overboard on 12 October while the ship was en route to Southampton. The body was later recovered with the involvement of the authorities. We are deeply saddened by this tragic event, and our thoughts are with the family. Out of respect for their privacy, we will not be providing further details."
The French authorities are leading the investigation into the incident. Channel Islands Air Search, lifeboat crews from Alderney and France, and a French helicopter based near Cherbourg were all involved in the search effort. Hampshire and Isle of Wight police are also assisting with inquiries.
The MSC Virtuosa, flagged under Malta, is 331 meters long and 43 meters wide, with capacity for up to 6,334 passengers and 1,704 crew. Built-in 2020, the vessel arrived in Southampton around 08:00 BST after departing from Cartagena, Spain.