I don't remember seeing anything limiting the size of the carry on. We carried on our rolling collapsible cooler with no problem. Just remember you do have to lug it around until your room is ready plus there is limited storage in the rooms.
I don't know if there's any official statute, but all carry-on luggage has to be passed through an airport-style metal detector. So it should be small enough for that.
I have read in my 7 day Magic Cruise documents that I have received, that they are limiting the carry on one per person plus a purse or briefcase. They were also giving dimensions 9" X 14" X 22" for the carryon. This is on page 7 of the Passport to Magic document. I was wondering if they are really enforcing that?
We took our soft sided rolling cooler as a carry on. I don't remember the dimensions but I believe it is larger than mentioned above. It did fit through the metal detector. We were planning to check it but was told they did not allow you to check drinks so we had to carry it on.
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