Avoid the Dangers by Knowing the Law
The point is, only open loop trips require passports, so you may want to see our article on Can a Felon Get a Passport? Not all countries allow felons to enter, or to obtain a visa, so you need to ensure you pay close attention to every port of call on your proposed itinerary. IT MAY NOT BE POSSIBLE FOR A FELON TO GET A VISA DEPENDING ON THE COUNTRY. If in doubt, double check with the official government websites of any foreign nations your cruise ship might be paying a call to. You can find visa, passport and other information about every country in the world here.
You can also contact a travel agent, but be advised they may not be experts on every issue; they are one point of information, but should not necessarily your only one. Similarly, you might wish to get in touch with your parole officer if you have one, not only to inform them of any upcoming desired trips, but to ask their advice.
Once you’re certain you can travel, make sure you communicate clearly with the cruise line itself. They can help you navigate any potential issues with any port of call embassies, in case there’s any chance at all of a hang up due to your prior felony conviction. The last thing you or they want is to land in legal hot water on the high seas!