I have T-Mobile. Just got off the Oosterdam. When on the ship always keep in airplane mode. I had the surf internet, and was able to make phone calls via the what’s app app over ships internet. Not a great connection, but it did work. When in port , you have data , calls at 25 cents a minute. You can buy a day pass for faster data for the day at I believe $5. Have been very satisfied with T-Mobile.