NTT Docomo Xi LTE 4G contract works for unlocked iPhone and Androids

Because NTT Docomo refuses to guarantee that unlocked phones from other carriers will work properly with Xi, here is the relevant portion of my January invoice that confirms there are no billing irregularities using the phone of my choice with a NTT Docomo Xi (LTE "4G") SIM card and contract. My feeling is that their refusal to simply say, "yeah, it should work - no problem," is because it absolves them of any responsibility if something did go wrong, which is, as far as I can tell, technically impossible. It also introduces enough doubt and concern to perhaps prompt someone to buy a new phone from Docomo.

Advantage of Xi over FOMA for Unlocked Phones

NOTE: Using a Xi SIM in a regular 3G handset will result in no increase in speed.

Even though Xi data is not unlimited (7 GB cap after which speed is throttled to 128 kbps), it is significantly better for non-docomo branded phones than a FOMA 3G contract. This is because the standard FOMA data APNs are filtered by IMEI number. Attempting to use any non-Docomo phone, or anything other than the two phones with IMEIs currently in Docomo's database, WILL result in no data connection to the (relatively) "inexpensive" APNs. The only way to open a working data connection with a FOMA SIM card is to set one of the APNs that add prohibitively expensive additional fees, either per packet charges or a tethering fee.

Docomo's treating of tethering with Xi is very reasonable. They don't add any extra charges and allow tethering.

Another potential advantage of Xi is the option for 24/7 free calling to other Docomo subscribers. However, this quickly becomes a pitfall if you often call non-Docomo subscribers because Xi voice plans contain zero free included minutes and no possibility of discounts to non-Docomo numbers. You can confirm if you are calling a Docomo number before the call connects. The standard beeping while the call is being placed (i.e., beep beep beep x3) is replaced by a voice saying "Docomo".

While the price for data is currently very good, this is a campaign price. From May 2012, the price will increase to the standard ¥5985, so I haven't listed price as an advantage.

Contracting Xi Service

There shouldn't be any real issues doing this, though I haven't personally started a new contract. I simply changed mine from FOMA to Xi. It should be as simple as walking in and asking for a new contract for Xi. There are both regular and micro SIMs available. If you run into trouble, ask to speak to someone else or go to another store. None of the J carriers make much of an attempt to educate store staff members on practices that are somewhat out of the ordinary.

(I actually had a young woman at a Docomo Shop tell me that SIM cards are locked, which is about the stupidest thing I've ever heard at any mobile phone store. They also apparently don't realize that the "special SIM" used when unlocking handsets is nothing but a non docomo SIM.)

The APN is mopera.net. Other details here.

A Xi micro SIM

Explanation of Invoice

For some reason, Japanese telcos feel compelled to make invoices overly complicated. It appears to be an attempt to show the customer how good a deal they are getting with unlimited contracts by listing many (often large) numbers and then subtracting them out. The irony is that, compared to the rest of the world, Japanese contacts are expensive.

	Expenses	Credits	Total
Base Fee	¥743		¥743
Voice Charges	¥2,440	¥2,440	¥0
International SMS	¥50	¥50*	¥0
Data (up to 7 GB)	¥4,200		¥4,200
U Standard ISP fee	¥500	¥500	¥0
Xi Talk 24	¥667		¥667
USC	¥5		¥5
Subtotal	¥5,615
5% Consumption Tax	¥281
TOTAL	¥5,896

With tax, this works out to ¥4,410 for 7 GB of data, of which I used 4.8 GB, and ¥1,480 for unlimited calls to Docomo subscribers. I made no calls to non-Docomo people using my cellular plan. Instead I used SIP, which provides much better rates to Japanese mobiles than any J carrier. Without the discount, Xi calls are billed at ¥21/30 seconds. The ¥2,440 amount of calls indicates I only used 58 minutes, which is not a lot but definitely enough to be worth paying the extra ¥700 for Talk 24.

The international SMS charges, which are the result of user error (replying to an SMS without using the Google Voice app - d'uh!), were offset by a credit carried over from previous months where I didn't use all of my included FOMA voice allotment. Because Xi voice plans include no allotment, this credit will no longer be available to me.

Points to consider when switching a FOMA handset to Xi

Main article is here. We have confirmation that it is indeed possible to purchase a FOMA handset and use it with a Xi contract while receiving monthly handset subsidies (i.e., 月々サポート). The trick is to immediately contract for Xi service upon purchase and NEVER have a FOMA contract. Canceling a FOMA contract cancels subsidies, period.

The flier I received when switching to Xi

• NTT Docomo will not guarantee that the flat rate will be applied, leaving open the possibility of per KB charges at ¥0.41/KB. (This information is not included on the flyer but comes via calls by the staff to the internal help desk.) **
• FOMA handsets will not support high-speed LTE data or contents exclusively for Xi handsets.
• Monthly handset subsidies will cease (i.e., 月々サポート), and if either "handset purchase support" (端末購入サポート) or "basic purchase support" (ベーシック購入サポート) is currently applied, a cancellation fee will be assessed.
• Xi Price plans and data flat rates will be applicable.
• The following FOMA handsets cannot be used with Xi*: HT-01A, HT-02A, HT-03A, HT1100, M702iS, M2501, M1000, M702iG, NM850iG, NM705i, NM706i, BlackBerry Bold, BlackBerry Bold 9700, BlackBerry Bold 9780, BlackBerry Curve 9300.
• Users of "Mopera U" and "Business Mopera Internet" should manually set the APN to mopera.net (consult the owner's manual for instructions).
• Users of third party ISPs may experience difficulty connecting to the internet or incur additional fees. Confirm if this is the case with your ISP before contracting Xi service.
• Users who switch back to FOMA from Xi will be ineligible for the "Value" voice plans unless purchasing a new FOMA handset (which will nearly double the price of the basic fee).
• A new Xi SIM costs ¥2,100, though it seems I was only charged ¥2,000 ¥2,000 + 5% tax = ¥2,100. (This information is not included on the flyer.)

* I can confirm that my ht-03a works perfectly fine with the Xi SIM. I even showed it to the staff at the shop (who really liked my splash screen, by the way). The staff member was aware of the custom ROM. He commented that perhaps it works but could cause billing issues. However, since my bill is so far normal, this doesn't appear to be the case.

** Technically, I don't see how this could happen unless Docomo specifically makes it happen, or you set some funky APN.