Check with your cellular carrier to see if it offers a cruise ship plan. Though it might not be cheap, it will be less expensive than international roaming charges. For example, AT&T offers packages priced at $30 for 50 minutes of phone calls, $60 for 50 minutes of calls and 100 texts, and $120 for the $60 plan with an additional 100MB of cellular data. Or, if you don't mind waiting to get to port to use your phone, you can opt for a land-based package such as T-Mobile's international service plan, which offers calls at $0.20 per minute, unlimited roaming and free texts in more than 140 countries.

Tip: Beware when you’re connected to "Cellular at Sea" or another at-sea provider; you’ll be hit with roaming charges of a hefty $2 a minute and, in many cases, more. 

If you’re planning to use your cellphone primarily for Internet — surfing websites, reading email, and posting to Instagram, Twitter, and Facebook — put your phone on airplane mode and use a Wi-Fi plan. Rates range from about $0.50 to more than $1 a minute, depending on the type of package you buy. Some cruise lines charge by bandwidth or offer a pay-as-you-go plan and a few — such as Regent Seven Seas Cruises — even include Wi-Fi in their cruise fares.

Tip: Royal Caribbean recently debuted a high-speed Internet service called Voom on its Oasis and Quantum-class ships that allows you to use Skype and other high-bandwidth apps that are blocked by some lines — at a quick-connecting speed that we haven't seen on cruise ships before. An unlimited package starts at $15 a day; on Majesty of the Seas, the service is free. This means you can surf and make phone calls for one price. Does your network and cellphone offer Wi-Fi calling? If so, you're all set. 

Carnival and Holland America Line provide packages designed specifically for social media use. Carnival's plan costs a mere $5 a day to use services like Twitter, Instagram, Facebook, and Snapchat — a value if your aim at sea is to stay connected to your friends and followers.

Tip: If you’re not itching to Tweet or post every minute of the cruise, forgo a costly Wi-Fi package and use your cellphone only as a camera or alarm clock; when you get on shore, head to an Internet café to log on to your favorite social media channels.

Check out your cruise ship's app — most major cruise lines offer one. Royal Caribbean International has a free Royal IQ app that provides all sorts of helpful info like ship maps and daily programs. For an additional $14.95, it also lets you make unlimited texts and calls to others on board who have the app — which can be especially useful on a large ship where it’s easy to lose sight of each other. Carnival Hub offers similar services for Carnival ships. You should also consider downloading messaging apps such as Signal, Viber, or WhatsApp that allow you to text, make video calls and share photos and files without racking up SMS or MMS charges (though you'll have to purchase a Wi-Fi plan onboard).

Tip: Disney Cruise Line's Navigator App features free messaging to keep in touch with others on board your cruise. You might also want to give group chat app FireChat or Jott, popular with teenagers, a spin; they work without use of a data plan or Wi-Fi connection. The catch? You have to be in close proximity to the person you're contacting.