I am going to Japan this coming May for 14 days traveling on JR pass from Tokyo to Hiroshima and loads of places in between. I have a new iPad Air wifi with unlocked SIM card. Do I need to just hire a sim or just a wifi portable device or both. I can't seem to find a definitive answer on this. I have downloaded maps off line and offline train apps and will use hotel wifi and JR rail wifi where possible but would like to have internet as backup for maps and self guided tours etc I would also like to be able to send the odd SMS or email. I have an iPhone but don't necessarily need to have access to it. Your help would be very much appreciated.