Minimum age to cruise: Babies must be 6 months to sail on most Cunard cruises. The exceptions are transatlantic, "exotic" and full world cruises, where the minimum age is 12 months.
Rules for cruising alone: Passengers must be 18 years old to travel on their own. Travelers ages 16 and younger cannot book a cabin without an adult 18 or over traveling in the same room. Children ages 16 and 17 can be in a cabin by themselves; however, they must be accompanied by an adult age 18 and over in a separate cabin.
Minimum age to leave the ship on your own: Passengers must be 18 or older to go on a ship-sponsored shore excursion on their own. Parents and guardians cannot leave anyone younger than 18 onboard the ship by themselves; an adult must stay on the ship with the minor at all times.
Shipboard venues with age restrictions: Passengers must be 18 or older (21 while in U.S. waters) to enter the casino and gamble and use the fitness center on their own. Children 16–17 may use the spa and gym if accompanied by a parent or guardian but are not allowed to use the weights.