I have Iphone through AT&T (US), plan paid for through work. No international roaming except in Canada. Unlocking SIM sounds extremely cumbersome... I'm not sure if I remember correctly, but I think AT&T told me they're not sure if my SIM can be unlocked but that I'd have to submit unlock request at least 3 days prior and then they'll decide if they'll allow the unlock. I don't have time to be messing around with stuff like that right before the trip.

As I understand it, my only option then is pocket wifi. Is that correct? But I can't be bothered with arranging for that ahead of time and having to pick it up, etc. So I just use my wife's Sprint phone which has free roaming in Jpn and HKG. But she doesn't like us sharing her device. Plus even though it's always showing as 3G, the connection is spotty... sometimes really fast, other times really sucks.

In terms of US wireless carriers, is Sprint the best carrier for free roaming in Jpn? (I'm admittedly quite ignorant about US cell phone system since I've always had someone else sign me up)