My Mum's going on cruise with stops in a few countries. She'll probably want to make an occasional call to book things, maybe use data occasionally.

What's the best way to get mobile access occasionally in those countries? Roam on 2degrees? With a pack of some kind, or standard rates?

Is there an international type SIM that's good value?

Is the LG G4 H815 ok for international roaming?

She might be best off using WiFi where she can find it, with Skype and such, and using the expensive ad-hoc roaming rates in emergencies.