The 18-month-old girl slipped from his arms and fell from the 11th floor of Royal Caribbean’s Freedom of the Seas ship.
The child is believed to have fallen onto the concrete below while the ship was docked in San Juan, Puerto Rico.
The tot was rushed to hospital at around 4:30 p.m. local time yesterday.
She was pronounced dead a short time later.
According to the local Primer Hora website, the girl was from Indiana and on holiday with her parents and grandparents.
Police have now launched an investigation and are trawling CCTV of the ship as well as interviewing passengers.