Sorry why would you want to add if you are just visiting? Do you understand the concept of putting money on there then spending it? It would seem like a bit of an overkill unless your holiday is quite long (being over 6 months) or you were planning on spending a lot of money on there at places that accept it to use this as you would lose anything left on the card balance wise plus more importantly i would imagine the effort you will have to goto to charge it wont be worth it.

I have to stick a usb adapter into my laptop then enter in a couple of passwords then scan the card like three times to charge my credit card to up my eddy balance which are all on the same card which seems all like a big overkill to me.

I did manage to get a free eddy activated card sent to me before i moved to Japan my registering online so it is possible. I think they are still running the free campaign but ask yourself... is it worth it?