Can I use my American iPhone 3G on Japan's Softbank service?

Discussion in 'iPhone Tips, Help and Troubleshooting' started by cphil19, Jan 12, 2010.

  1. cphil19 macrumors newbie

    Jan 12, 2010
    Hi everyone,

    I'm new to the world of the IPhone so excuse me if the answers to my questions are obvious ones. Basically, I'm moving to Japan in about a week and am lucky enough to be eligible for a phone upgrade with Att, meaning I'd only have to pay about a hundred bucks for a new iphone (It's actually on my brother's account who doesn't care if he needs to sign another two year agreement). So, my question is, if I buy a new iphone here from Att, could I bring it over to Japan and use it with Softbank's service? I already have Softbank service/sim card (thanks to my Japanese gf) so getting a sim wouldn't be a problem, I just wanted to make sure that after I buy the phone, I could just slip the softbank sim card into my iphone and it would work without a hitch. And when I say work, I mean not just phone functionality but apps/internet/all that good stuff as well. Thanks guys!
  2. nastebu macrumors 6502

    May 5, 2008

    The AT&T phone is locked, and so you'd have to jailbreak it. After you jailbreak it, I still *think* you'd have to take it in to Softbank to get it set up.

    If it's going to cost you $100 for the phone anyway, you might look at Softbank's plans. I bought an iPhone from them, with a contract, and it didn't come out to much more or less than $100. I did buy it with a two year contract though.
  3. cphil19 thread starter macrumors newbie

    Jan 12, 2010
    Thats the thing though, my girlfriend already has Softbank service, so if I were to buy an iPhone through Softbank directly, I would paying full retail price which I imagine would be aroun the $500 range.....
  4. bradl macrumors 68040


    Jun 16, 2008
    You would still have to unlock the iPhone to take it to another carrier.

    Also, something to think about. Be sure that Softbank uses the same 3G bands as ATT. Otherwise, you'll end up in the same situation with Softbank that those with unlocked iPhones have with T-Mobile (T-Mobile USA's 3G is on a different band than ATTs, so a jailbroken and unlocked iPhone can only use Edge on T-Mobile).

    If they use the same band, then you just purchase a plan with Softbank, they give you a new sim card, and off you go.

  5. cphil19 thread starter macrumors newbie

    Jan 12, 2010
    Some way I can find out?
  6. bradl macrumors 68040


    Jun 16, 2008
    Wikipedia and Google are your friends:
    They should be using quad-band GSM over there, so 850/900/1900/2100 should be it. ATT uses 850/1900, so you should be fine. a double-check on an iPhone/Softbank forum wouldn't hurt.

  7. cphil19 thread starter macrumors newbie

    Jan 12, 2010
    Unfortunately, there aren't many Softbank/iPhone forums out there, and the ones that do exist have very conflicting information. Soooo yea, not sure where to go from here.
  8. bevman macrumors newbie

    Jan 23, 2010
    I am active duty military stationed in Japan. And highly suggest you just get one here.

    Softbank is offering the iPhone for reasonable prices. This is due to the Japanese not liking the iPhone.

    3G 8gb for free w/ 2 year contract.
    3Gs 16GB add 495 yen a month x 24 months (about $5)
    3Gs 32gb add 950 yen a month x 24 months (about $10)

    The Japanese pay for their phones in addition to their monthly service kind of like a loan.

    The really bad news is one of my junior sailors was "lucky" enough to buy a Softbank iPhone before leaving the states. He then took the phone to Softbank and found out that setting up their own phone was more expensive then just getting a new iPhone under contract. He ended up getting a new one.
  9. bevman macrumors newbie

    Jan 23, 2010
    This would really suck...... Japan's 2g (EDGE) service is soon to be gone. Huge sign at my Softbank store. I forget what the date is, but it will be gone soon.
  10. ukcolinr macrumors regular

    May 12, 2009
    All iPhones are manufactured the same (with the exception of the Chinese model without WiFi) I've used my UK iPhone (Which also works with an AT&T SIM in the US) in Japan with no problems at all, you just have to make sure 3G is enabled, it took me 24hours to figure out the reason I wasn't getting signal in Japan was because 3G was Disabled and there's no 2G in Japan (at least not in Narita or Tokyo Disney Resort) lol

    If the handset works in a country with a foreign SIM, providing the handset is not SIM-locked it will work with a local SIM also.
  11. longrowe macrumors newbie

    Feb 26, 2009
    Will your iphone physically work, Yes. Will the data charges cap, Maybe.

    Unless your GF was lucky enough to get you a Softbank "iPhone" sim card, you will just be on a regular 3G plan, so there will be no cap on the data. The charges will continue to accumulate. Softbank will not sell the iPhone sim card unless you buy an iPhone from them, or if you are an existing iPhone customer and have lost/damaged your sim and need a replacement. That is it. It isn't as easy to fake the cell companies here as it is in the US. They do not have open telecommunications laws so the carriers lock the users to their service and routinely check IMEI numbers to make sure you phone is "authorized" to work on their network.

    be wary...

    this is a really long thread but these guys can answer your questions if you post in it:
  12. clammy77 macrumors newbie

    Feb 11, 2008
    So, my situation is this.
    1. I have an unlocked iPhone 4 bought from the states.
    2. I already have an iPhone 3GS from Softbank, and I have the unlimited plan for the iPhone, and I have the iPhone sim card.

    My question: Will I get charged for the famous overage since their system can see the IMEI of my unlocked iPhone that's not one of their devices. I have read somewhere saying that I am okay if I have the iPhone sim instead of the normal gray sim.

    I know that the previous post said that it works, but i mean, i'm saying will I get the cap on my data plan?

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