Your IP address will be an internal one...e.g., 192.168.xxx.xxx...you won't be assigned a publicly addressable IP.
What you really want to know if the IP of MSC's router
Think about it this way...at home, you have a bunch of devices connected to your wifi...they all will have addresses starting with 192.168.xxx.xxx. However, if you ping an external site, that will register with the IP of your router (or modem, or whatever device brings you wifi).
I'm not sure anyone can answer you what that will be. The reason is, it should vary by how MSC connects to the internet. It will vary from ship to ship and possibly multiple times on the cruise if multiple providers are involved.
Furthermore, the provider should be satellite, which isn't a "country" and usually assign *dynamic* IP addresses.