Short Answer: What is allowed/not allowed is determined by the U.S. Customs and Border Protection (CBP), as well as individual cruise line.
Long Answer: Don’t bring anything you don’t want the U.S. Customs and Border Protection finding. Also, don’t bring anything outlined by the individual cruise line.
I’ve shared some links below to help answer this question.
- Norwegian’s policy: http://www.ncl.com/faq#what-to-bring
- Carnival’s policy (2 links):
- Royal Caribbean’s policy: https://www.royalcaribbean.com/faq/questions/prohibited-items-onboard-policy
This is not the single definitive answer. Be sure to contact the individual cruise line, Groove Cruise, or the CBP if you have any questions.