I highly recommend you rent or purchase phone in Japan. Really easy to do, and reasonably priced for calls to US. I have a BB8830 that my company promised would work, but after 5 calls from Verizon support to my hotel, they couldn't get it to work, and stopped calling. They never told me they had no resolution, they just stopped contacting me. They called me because my company support couldn't resolve the problem, and requested their help. I believe Japan went all 2100 MHz 3G-only....I saw it on a Q&A site, so can't determine it's reliability, and don't remember site, sorry.