B-Mobile Prepaid SIM Card

An update to the Japanese mobile phone situation

06 May, 2013 by

Some time ago we looked at the Japanese SIM card rental options and deduced that if you’re visiting for a short holiday, the best thing to do would be to stick with your local carrier’s roaming plan. The situation’s changed quite a bit since then and many of the previous SIM card options are now defunct, though the previous conclusion still stands. However for those staying for a longer duration or who require internet access on the go, B-Mobile’s prepaid data cards provide an excellent alternative.

Following the rise of smart phones in Japan, B-Mobile began marketing their local 3G  enabled prepaid data SIM cards between the end of 2010 and 2011. For roughly 3,000 yen, B-Mobile’s data cards offer a month’s worth of data usage. They tap onto the existing NTT DoCoMo networks to provide speedy mobile internet access to just about any part of Japan. Recognizing the demand for data cards by foreigners visiting Japan, B-Mobile have also released special “Visitor Sim” cards last year though I wouldn’t recommend them for reasons explained below.

B-Mobile offers a wide range of different prepaid cards for sale off the shelf at most major electronic shops in Japan like Yodobashi Camera or Bic Camera. Their data cards are available in standard, Micro and Nano sized SIMs (at least for the newer SIMs). Do make sure that you get the correctly labelled package, otherwise you’d have to find some means to cut the card to the desired size.

It is important to note that all of the B-Mobile SIMs are data-only, giving you mobile internet access in Japan, but no traditional phone time or SMS. You can see the full range of B-Mobile products here, however only a few are relevant to travellers, their classic U300 and 1GB Fixed cards and their rebranded equivalents targeted at tourists.

B-Mobile U300 Data SIM

U300. 1 month of unlimited data capped at 300kbps.


The first data SIM card that was offered by B-Mobile is the U300. U300 in this case stands for Unlimited 300 as the U300 data card gives users unlimited data access for a month, which is capped at 300kbps. There are also additional limits to the U300 card in that it does not allow for Voice Over IP services like Skype or LINE or streaming videos. Sustained streaming have been disabled in the card.

The U300 card is the cheapest at 2,980 yen. Given these limitations though, there is little point for unlimited data access, but if you find yourself in Japan without any other forms of internet access this may be attractive to some visitors. The lack of phone calls may be overcoming by using a messaging application.

Since the U300 is considered an older product, you may have a little bit of trouble finding it at out of the way electronic stores. Sometimes it is not displayed prominently either, leading some to believe that they are not available in stores. In the case that you do not see it displayed, some have had luck asking the sales staff at the electronic stores as they may be tucked away with the rest of the less sellable stocks.

B-Mobile 1GB Fixed Data SIM

1GB Fixed. 1gb of uncapped data usable over a month.

1GB Fixed

The second data card introduced and the one that should interest most visitors is the B-Mobile 1GB Fixed data SIM. It costs slightly more at 3,480 yen but removes the restrictions on VoIP and streaming services. The access speed is also not capped at 300kbps, allowing for lightning fast 3G and 4G LTE access. Our experience with the 1GB Fixed card speeds was very satisfactory. Being Japan, we found the internet access to be much faster than any equivalent Singapore connections, even while traveling on the train, in the middle of the countryside. The downside to this is that data access is capped at 1GB.

With VoIP, one can use services like Skype or LINE to replace the occasional call in Japan. The 1GB data limit is sufficient for a couple hours of total calls and just about as much messaging or surfing you’d ned for a month. If you’re on holiday in Japan and using anything more than that, chances are you’re not enjoying the trip to its fullest.

Note: The one and biggest downside to the above two SIM Cards is that they were only created with the local user in mind and were meant to supplement existing lines. In order to begin using the B-Mobile data SIMs you will need to dial up a toll-free number and enter the product code into the automated systems with normal Japanese cellphone.

If you have access to a friend in Japan who can do this for you, then this is a minor issue. Picking up the U300 or a 1GB data card directly from an electronic store is the cheapest option, since you can forgo any extra shipping charges. However in our last trip, we found it extremely difficult to get anyone to help. I have heard stories where the shop assistants at certain electronic retailers would help tourists to activate their cards, but this is not the norm. In fact with the new B-Mobile Visitor cards, I might suspect some have been told not to.

Getting the SIM card to work without the help of a Japanese friend is much more troublesome. B-Mobile offers a hotline that can be accessed by landline, however to deter tourists from using this SIM activating your card this way now costs an additional 2,500 yen.

One possible solution is to get the B-Mobile data SIMs through local resellers. There are people living in Japan who have taken the opportunity to sell pre-activated B-Mobile cards albeit at a heavily marked up price. This should only be considered if you’re planning to stay in Japan for more than 14 days. Getting a reseller to activate the card and then ship it to you not only costs more, but you’d also be losing at least one day of data access in the process.

B-Mobile Visitor SIM

Visitor SIMs. More expensive, less days.

Visitor SIM 14-days Prepaid and Visitor SIM 1GB Prepaid

The Visitor SIM 14-days Prepaid and Visitor SIM 1GB Prepaid cards are the two B-Mobiles SIM cards targeted toward tourists and they follow the typical Japanese practice of taking foreigners for suckers.

If you’re visiting the B-Mobile website in anything other Japanese, these will be the only two cards that are displayed to visitors. Both cards are identical to the the regular U300 and 1GB Fixed cards respectively, with the exception that data access is capped to only 14 days, rather than the usual month.

As if that wasn’t bad enough, the visitor SIMs also cost more than their Japanese counterparts at 3,980 yen each.

However, if you’re only planning to stay in Japan for a maximum of 14 days and want to do without the hassle of getting the SIM card activated yourself, the Visitor SIM 1GB Prepaid is still a viable alternative as the prices for the visitor cards are inclusive of delivery charges to your hotel when ordered online. All the cards come pre-activated so you can place an order in advance and have it delivered on the day in which you arrive at a hotel for maximum convenience. Airport pickups are also available but cost an additional 210 yen more.

Edit: The B-Mobile link above shows which SIM cards are available in which sizes, but for clarity do take note that only the newer Vistor cards are available as Nano size SIMs. The local versions of the U300 and 1GB Fixed are available in standard and micro sizes only.

Planning your holiday? We recommend visiting Agoda for a full list of hotels with early bird specials.


Supermerlion's Webmaster and Editor-in-Chief. Singaporean Nikkeijin with over 12 years of experience in the media industry. Producer at a Japanese entertainment company. Former Web Developer, Graphic Designer, Multimedia Programmer, Manager and Consultant. Shoots with a Canon 5Dmk2 and Sony RX100-2.