I was wondering about the same issue in the original post.
I live in the UK, and have just acquired my first smartphone. I have taken a contract with 3 mobile as I spend a lot of time in France and, as stated above, 3 allows use of your monthly allowance of calls and texts to UK phones, and data use, without extra roaming charge.
My daughter insisted however that I switch "data roaming" off unless I really needed it.
I am a bit dense about all this still, but I find that even with data roaming switched off, my geocaching app functions normally, so I suppose it is using the 3g network.
My question is:
As I am in France at present, is it going to incur extra phone cost to geocache in this way? It is working very well here.
What is the app connecting to? If 3g, then does that mean a phone number? And if so, would it be a local one in France (for which I know I would have extra to pay)? Or is it linking back to. UK phone number, in which case I think there will be nothing for me to pay extra to 3 mobile.
Or should I switch data roaming back on, and somehow disable the 3g connection? Is this even possible?
Angela