I noticed a pattern on B-Mobile's website--a pattern that seemed to show that all Docomo Xi phones can get LTE. Since Docomo just started selling the iPhone 5s and 5c, my theory was that Docomo iPhones would get LTE on B-Mobile. I couldn't get LTE on my unlocked iPhone 5 (a thorn in my side), and I just love testing IT-related theories, so...
1. I bought a Docomo iPhone 5s on Yahoo Auctions Japan. There's no way in hell I was going to enter a 2-year contract to get one direct from Docomo. I'm a typical man with a typical fear of commitment. I would have waited had I known the Japan Apple Store would finally start selling unlocked iPhones (yeah!), but my fortune-telling skills are something to be desired. At least it will be easier to get an unlocked iPhone 6 in Japan.
2. I put my B-Mobile SIM card in and restored my iPhone 5 backup to the new 5s. It worked! It even got LTE.
But some things were amiss...
Where are the APN settings?
The Docomo iPhone 5s is locked (of course), and they locked-down the setting screens that allow you to enter the B-Mobile APN settings. My phone worked because the APN settings were restored from my backup. I was a bit worried about this because swapping SIM cards or (more rarely) iOS upgrades can blow-out the APN settings, forcing you to reenter them. This was not an issue on my unlocked iPhone because the setting screens were there. But now they weren't. What to do?
Again my buddy Professor Research directed me to this post from Apple: http://support.apple.com/kb/HT4839?viewlocale=en_US&locale=en_US
Basically you can download the free "iPhone Configuration Utility" from Apple, create a custom configuration profile containing the APN settings, and install it on the iPhone. Nice! Now I'm relieved because it means I can indeed use the Docomo iPhone 5s with B-Mobile. In fact, B-Mobile even offers a downloadable ready-to-go configuration profile on their website: http://www.bmobile.ne.jp/devices/setting_iphone_profile.html
What about tethering?
Tethering (aka "personal hotspot") doesn't work. Boooooo!
When it comes to iPhones and B-Mobile, you can't have it all out of the box:
* You get LTE on a locked Docomo iPhone, but no tethering.
* You get tethering on an unlocked iPhone, but no LTE.
For someone like me that wants it ALL, here are the options:
* Jailbreak this damn Docomo phone and install a tethering app.
* Use an Android Docomo Xi phone instead. Docomo will actually unlock those, and they're more generous when it comes to things like tethering. Now if only they had an Android phone that wasn't freakin' HUGE and loaded with DoCoMo bloatware.
UPDATE - 2013/12/5
Japan's Apple store has finally started selling unlocked iPhones! Nice! Now a new door has opened for those of us living in Japan. Unfortunately, according to a kind reader (comment below), the unlocked iPhone from the Japan Apple Store cannot tether on B-mobile. So sad...maybe someday...
B-Mobile on Amazon Japan: Amazon Japan - B-Mobile