Cruise lines quote their prices on a per person basis, based on double occupancy. So if you want to cruise solo and have a stateroom to yourself, you normally have to pay a surcharge. This is understandable, but annoying for the person who wants to take a cruise alone.
Three cruise lines have special single occupancy cabins for solo cruises.
Norwegian Cruise Line has Studio cabins for solo travelers. They are available on the Norwegian Escape, Norwegian Bliss, Norwegian Breakaway, Norwegian Getaway, Norwegian Epic and Pride of America. Studio guests have exclusive access to a shared lounge.
The luxurious Cunard Line offers single staterooms across its entire fleet. They are located on the same decks as popular public areas. Amenities include 24-hour room service, traditional afternoon tea, live music, lectures, and fine dining.
American Cruise Lines has some single occupancy staterooms for solo travelers on its ships, including the Queen of the Mississippi. It is a paddlewheel ship that offers cruises on the Mississippi River.