Be a company shareholder. If you hold at least 100 shares in Carnival Corporation, you will receive $250 worth of onboard credit for cruises that last 14 days or longer, $100 credit for cruises lasting seven to 13 days, and $50 worth of credit for cruising six days or less.
The amount of credits offered to shareholders changes periodically, so check back often with Carnival for the most up-to-date amounts.
Book a promotional cruise. Periodically Carnival will offer incentives to book cruises that may not fill up because it is traveling to a destination in the off-season. Carnival will sometimes offer free onboard credits to anyone who books a cruise for a certain time period, itinerary or specific ship.
In the summer of 2010, Carnival had a special promotion of free stateroom upgrades and up to $160 in onboard credit for cruises traveling between August 2010 and February 2011. Check back on Carnival's website regularly for future promotions.
Use your Carnival MasterCard. Whenever you use your Carnival MasterCard, you earn "FunPoints" that are redeemable for free items when you're on your cruise. Only MasterCard transactions made on your card count toward Fun Points (not debit purchases or ATM withdrawals). You can use 1 FunPoint for each dollar spent on transactions and 2 FunPoints for any Carnival Cruise purchases, including those made onboard.
Have family and friends purchase onboard credit for you. Carnival Cruise Lines allows friends and family to purchase onboard credit and coupons for you prior to your cruise. If this is a wedding or honeymoon trip, you can sign up for the Carnival Cruise Gift Registry and people can purchase services that you can partake in on the ship, such as a state room upgrade, breakfast in bed, casino credit, free dinners and spa services.
