No, its not an app. Its a shortcut to the princess website. We loved it for showing us the itinerary of the day. It allows you to highlight what you want to do and see and send it to someone else. You can also use it to send messages to other friends onboard. It wont alert you when you have a message so you have to open the app to see if anyone sent you a message. Coverage of the onboard wifi is not good in certain places aboard ship. No cost for use.
84634 about Princess Cruises Messenger, v1.0.7