The woman went overboard sometime on Saturday night into Sunday morning (August 18-19) while the ship, Norwegian Star, was 60 miles off the coast of Croatia.
Named as 46-year-old Kay Longstaff, the Press Association reports she told rescuers her yoga fitness and singing kept her going through the night.
She reportedly told Croatian news channel HRT she fell from the back of the deck and was in the water for around 10 hours in total.
In a statement, the line said: “On 8/19, a guest went overboard as Norwegian Star made her way to Venice. The coastguard was notified and a search operation ensued.
“The guest was found alive and has been taken ashore for treatment. We are happy the individual is safe and will be reunited with friends and family.
The woman was taken to hospital in Pula following the incident.
A search and rescue operation as launched at 2.17am on Sunday said the coastguard.
She was located shortly before 10am on Sunday by the Cavtat coastguard crew.