There are no ferries from Cancun/Jamaica to Cuba or viceversa. You can though rent a boat in Cancun or Mexico and arrive to any of the Marinas available in Cuba. You will have to return the boat to its origin though.
You can get a flight from Cancun or Jamaica to Havana or Santiago de Cuba. There are 2 flights a day with Mexicana and Air Jamaica respectively at the cost depending on the season is around $300.00.
Our specialists have published on this website some of the most interesting tailor made package holidays to Cuba. Feel free to browse our list of package holidays and get quotations online.