Posted May 19th, 2018, 05:47 PM
No one can answer your question with the information provided. You're getting a bunch of answers, none of which may apply to you (e.g., you may or may not consider $2.50/minute prohibitively expensive, and you've asked about using your phone, so you've already decided that turning it off and putting it away is not your preferred course of action).
Who is your domestic provider?
What phone do you have? (not just iPhone, but iPhone 5, 6, 6S, etc.)
Will you have an onboard wifi package? Unlimited?
Each domestic carrier has its own program. Most (I believe AT&T is an exception) do not include the ship in their international roaming packages. Almost all have some sort of international roaming package. Almost all current generation smartphones, even CDMA phones on Sprint or Verizon, will roam on GSM service outside the United States. Most if not all current generation smartphones and carriers will allow you to use wifi calling to make calls over the internet without "roaming" or requiring a third party app such as Facebook messenger or Whatsapp.
Almost all of the answers to your questions are on your carrier's website under international roaming. Verizon, for instance, allows you to enter international destinations and cruise ship name and will give you your options for using your phone.
Brilliance of the Seas July 2015
Explorer of the Seas June 2014
Freedom of the Seas July 2013
Jewel of the Seas July 2012
Freedom of the Seas April 2011
Oasis of the Seas March 27, 2010
Independence of the Seas April 2009
Liberty of the Seas March 2008
Maasdam August 2006
Oosterdam December 2004