Carnival's rules just went affect while Royal Caribbean's ban has been in place longer but has some exceptions.

On Royal Caribbean’s ships, Starbucks drinks are not included in any drink package, while hand-crafted beverages from Café Promenade (which use Starbucks coffee) are. Plus, the beverages sold at Starbucks are significantly more expensive than comparable drinks served at the alternative.

And for those who want to celebrate their special day with family and friends, a cruise can be the ultimate birthday party. Even if you don’t want a party, there are plenty of ways to treat yourself on a birthday cruise — from pampering yourself at the spa and indulging in a specialty dining experience to embarking on a bucket-list shore excursion.