Cruises: What are the age restrictions for passengers? Who is banned from travelling?

Are some passengers banned from having a cabin on their own?

Yes, those below the age of 18 will have to share with another family member over that age.

The following cruise lines require that at least one person in each cabin is 21 or older: Costa, Crystal Cruises, Delta Queen Steamboat Company, MSC Cruises, Norwegian Cruise Line, and Seabourn Cruise Line.

The following cruise lines require that either all passengers in a cabin must be 21 or older, or if anyone in the cabin is younger than 21 years old, someone in the cabin must be 25 or older: Carnival, Celebrity, Royal Caribbean, Holland America, and Windstar Cruises.