Cell phones may work in some ports, not on CC, possibly at sea if you are near land with cell tours.
Every cell phone company has different coverage, different plans, different fees, so information you get from someone on here may not apply to your phone and your plan.
What we did was call our provider a few weeks before going. We had a list of the ports we would be at and we went through them one at a time. They were able to quickly tell us whether they had service in those ports and whether or not it was covered by our specific plan or if we would have to pay roaming fees.
The answers we got did differ from information that I had seen posted for the same cell carrier. In one case it was because the poster on here had a different plan and in another, the situation had just changed, our company added service to a port that they hadn't had before.
There was one other big plus for calling. Some phones have to be updated with the current tower information. Because our company had just added service in one port, we needed to get our phones updated. We were able to do that before we left. My sister who has the same carrier did not get her phone updated and her phone didn't work.
So best advice is to call your provider so that you get the information about coverage and costs that applies to your phone and your plan.