Oversea cell phone usage (Tokyo)

Hi guys,

I will be traveling to Japan next month and I did some reading on the usage of cell phones from overseas. I think I will not end up without a working phone, but I thought of double checking on this forum :)

so I have an iPhone 5 with a Turkish SIM card and a Blackberry with Belgian SIM card. Both activated for roaming. Can anyone confirm I will be able to stay connected upon arrival?

If not, happy to get some tips on renting a SIM card at the Airport.

Thanks a lot,

Molun