As long as they have your name, ships name, and cabin nos., they can call 1-800-Carnival and be connected ship-to-shore. You'd have to be in your cabin to rx the call but they'd take a message. It's about $10 a minute for that service.
Friends and family may call guests onboard via Maritime Telecommunications Network (MTN) Shore-to-Ship telephone service. The rate is $9.50 per minute from the United States; additional long distance charges may apply from outside the United States.
The caller needs to have available the ship name and the guest's name. The charges will be applied to the caller's credit card: MasterCard - Visa - American Express - The Discover Card - Diner's Club. 1-877 CCLSHIP (1-877-225-7447) from the U.S. 1-732-335-3284 from Canada and outside the U.S.
There is usually an explanation of this with your cruise documents. There has been a change in cell phone usage on cruise ships, and also the old stanby 1-800-SHIP or whatever it is that is always available.
Freedom Of The Seas -07
Radiance Of The Seas-07
Adventure Of The Seas-05
Navigator Of The Seas-04
Soverign Of The Seas-02
Big Red Boat-93