How to use your own cellphone/iPhone in Japan, by purchasing a prepaid SIM card or renting a SIM card is often one of the most commonly asked questions on travel forums. This guide will help provide the answer, with a comparison of the different costs involved because surprisingly, there aren’t any clear articles dedicated to how to use your phone in Japan.
For reference, the main networks in Japan are NTT DoCoMo (largest), au by KDDI (second largest) and Softbank Mobile (formerly known as Vodafone Japan).
While it is possible to obtain a SIM card in Singapore as long as you are able to provide a valid passport or ID for registration, getting a loose prepaid card in Japan is impossible unless you are able to present a “Certificate of Alien Registration” with a visa longer than 90 days, as well as a proof of Japanese address.
To put it simply, if you are coming to Japan on a holiday, there are no prepaid SIM cards you can use on your own cellphone.
KDDI does offer a prepaid option that can only be used on a specific phone set, which you will have to purchase at full price. Not only is the cost ridiculous, the phone is limited to only basic calling functions (no 3G or e-mails).
SIM Card Rental
With prepaid SIMs out of the question. The only options left for those who still wish to use a Japanese line on a trip is to rent a post-paid SIM card. From the moment you step out of the plane, there are a number of shops in the airport providing such services.
Softbank is currently the cheapest provider. The company rents out SIM cards for use with your own phone. However, Softbank has recently terminated all their non-3G networks so their SIM cards will only work with 3G phones now. You can rent a 3G Phone + SIM card combo if you’re one of the few people who don’t own a 3G phone.
It costs 105 yen ($1.70) a day just to rent the card and 250 yen ($4) per day to rent a phone and card together (for the current promotional period). Local calls cost 105 yen ($1.70) a minute, while messages are 15 yen ($0.24) each. For reference, calls to Singapore cost 300 yen/minute ($4.80). All incoming calls and messages regardless of origin, are free. Still even if you were to ignore the daily rental cost, using a rented SIM can be pretty expensive.
Both regular calls as well as 3G data services are usable with Softbank SIMs. Though for some reason, their cards are not compatible with the iPhone 4 (older models work fine).
It may come as a surprise to some that roaming with your existing mobile contract from your own country will actually work out to be even cheaper than using a Japanese SIM card.
Not only do you not have to pay a daily rental charge, actual usage is cheaper in all aspects to a rented phone. Interesting, it’s actually cheaper to roam in Japan with a Singapore subscription, than what it costs to roam in Singapore normally.
In the future, costs could be further reduced with the new Conexus Mobile Alliance, a collaboration of operators with aims to provide cheaper roaming charges.
The main thing to take note of is that it usually costs a monthly fee to activate roaming services. For Singaporeans with an existing line, you can still make calls with without registering for roaming, but will instead be charge an extra 20% surcharge on all charges.
Another downside to using your existing mobile contract in Japan is the lack of free incoming calls, which can work out to a bit if you are expecting a lot of overseas correspondence or if you forget to inform your friends that you are going overseas.
Still, it should end up significantly cheaper than renting a Japanese SIM card.
This option, is only applicable to those without an existing contract. It is mostly shown here for price comparison sake. It can be a viable alternative for those who are not expecting to make many phone calls but still require a means of communication with the other people you are traveling with.
The down side is that roaming calls are more expensive on prepaid cards than on regular subscriptions. When it comes to prepaid roaming SIMs in Singapore, M1 offers the cheapest rates. SMS and roaming charges are not so different from roaming with a regular line and calls back to a Singapore number are even cheaper than a line without a roaming subscription.
And finally, a comparison charge on the costs involved, with Singapore networks as an example. Charges for post-paid lines are in addition to whatever you’re already paying per month. Prices are for with and without the optional roaming subscription. Bold text are the cheapest prices in comparison.
In summary, don’t bother renting a Japanese phone or SIM card unless you are receiving a large number of calls each day. For normal usage, calling out with a foreign line works out to be cheaper.
Edit: If you don’t mind using a data-only SIM, the B-Mobile Prepaid SIM Card is a good alternative that will give you 3G or 4G data access all around Japan, and will also likely be the cheapest option.