What are the options for getting a smart phone up and running when travelling for a couple of weeks in Japan?
Right, with a bit of research, I've put the following together.
Modern Japanese mobile phones (携帯電話 keitai denwa or just keitai) tend to operate on unique cellular standards not always compatible with the rest of the world. For instance, most Japanese 2G mobile phones operate on the Personal Digital Cellular (PDC) standard, which was developed and is used exclusively in Japan. In a nutshell:
If your phone is up to spec, double-check with your carrier if they have a roaming agreement with either SoftBank or NTT DoCoMo. Coverage is generally excellent, unless you are heading to some remote mountainous areas.
If you have no 3G phone but still have a 3G-compatible SIM card, you can rent a 3G phone in Japan and slot in your card, allowing you to keep your home phone number in Japan. Carrier restrictions may apply: for instance, O2-UK (operating in Japan via NTT DoCoMo) requires you to dial 111#, wait for a callback; then, dial the actual number you wish to connect. Be sure to double-check with your network provider before departing.
GSM-only SIMs are issued by providers that don't have their own 3G network. If your home operator have no 3G network, or if you got your phone before their 3G network was introduced, this may apply to you. Call and ask your operator if their SIM cards are USIM compatible.
USIM cards are issued by providers that have a 3G network or plan to introduce one. Any European who got their SIM card after 2003 has one of these. Call and ask your operator if their SIM cards are USIM compatible.
Data roaming works as well (subject to the above restrictions), allowing you to use wireless internet on your phone (although it can be expensive!). Google Maps on your phone can be invaluable (although note that tower positioning does not work).
For a short visit, your cheapest option for mobile access is to rent a phone. A number of companies provide this service. Rental rates and call charges vary, the best one can depend on how long you are renting and how much you will call.
Beware of "free" rental as there is a catch: usually, there are very high call charges. Incoming calls are free in Japan.
Mobal Communications Inc.
Free rental (meaning there is no expense unless you actually call someone). ¥240/min domestic and international. Very expensive (around $3) - have people call you instead, since incoming calls are free. Be careful not to lose the phone or the charger as the company charges horrendous amounts.
¥3,900 up to one week, then ¥300/day. Shipping included. ¥35/min~ domestic. USA ¥45/min. ¥300 for unlimited emailing. You can also use your SIM in the phones. Offers customers a choice of phones.
Japan Mobile Rental
¥1,200 per day for unlimited broadband internet Connect up to 5 devices Install Skype on your PC or phone and take advantage of cheap international calling rates Use in virtually any place in Japan Pick-up at our Narita or Kansai Airport counters, or at your hotel.
SoftBank Global Rental
¥250/day; SIM card: ¥105/day. * ¥105/min domestic. USA ¥105/min. Incoming calls are free. iPhone SIM Rental(3GS/4) is available. ¥1,500 per day for iPhone unlimited data communications.
"Free rental" for the first week, but you must pay for shipping at rather high rates working out at at least $30. After that $2/day. $0.70/min domestic. USA $0.90/min. Incoming calls are free. Extra $10 use email. Service tax of 15% added to final bill. Run from the US by the people who run Panda Phone (Chinese phone rental).
¥525/day. Extra shipping charge of ¥800-1800 if you want the phone delivered.. ¥90/min domestic. USA ¥100/min (daytime). Incoming calls are free. ¥315 extra if you want to know the phone number in advance.
¥2,995/week with 15 free minutes, plus ¥1,000 for shipping. ¥85/min domestic. International ¥100/min. Incoming calls are free. Final credit card charge can be up to 2 months after return.
¥315/day (rental fee waived for ANA passengers). Extra shipping charge of ¥1,575 if you want the phone delivered. ¥120/min domestic. International ¥150/min. Incoming calls are free. ¥315 extra if you want to know the phone number in advance.
¥200/day ¥100/min domestic (NO international calls) or ¥160/min omestic and international. Incoming calls are free.
Mobile Phone Japan
¥2,900 up to one week / ¥5,600 up to two weeks. Shipping included. ¥90/min domestic. USA ¥78/min. Prepaid phones - you need to buy a top-up card if the credit runs out Must reserve at least one week in advance of arrival.
Global Advanced Communications
iPhone ¥8,000/week with unlimited internet access. Delivery charge included. ¥24/min domestic and international. Cell Phone ¥3,500 up to one week, then ¥300/day. ¥18/min domestic. USA ¥16/min (using call-back). Data card for laptop ¥4,500/3days with unlimited internet access. Must reserve at least 4 days in advance of arrival. Not open at weekends.
They have a complicated array of plans, the basic one (plan B) : $75 up to one week $130 up to two weeks + obligatory insurance $15). Shipping to hotels included; $10 extra to airports. $0.90/min domestic. USA $1.35/min. Run from the US
Japanese phones have an email address linked to the phone number, and most of the above companies allow you to send and receive emails. Your usual email provider may offer redirection to another email address (GMail does), so that you receive all emails on the cellphone. Beware that companies charge for incoming and outgoing emails.
For a longer trip, you can also purchase a phone, but doing this legally requires an Alien Registration Card (or an obliging Japanese friend willing to front for you).
The easier way is to get a prepaid (プリペイド) phone. Prepaid phones are sold in most SoftBank and au stores (NTT DoCoMo does not have prepaid phone services anymore). Stores located in important areas of major cities in Japan often have English-speaking staff to help foreigners, but this should be confirmed prior to visiting the store. If you already have a 3G phone, go with Softbank as it can sell SIMs as opposed to au whose prepaid service is phone-based like most CDMA carriers.
Prepaid phones use a "card" with a pass key to "charge" a phone with minutes. These prepaid calling cards, unlike the phone itself, can be found in most convenience stores.
A prepaid cell phone is available for as little as ¥5000 plus ¥3000 for a 60-90 day call time package, which will get drained at a rate of ¥100 per minute (¥10 per 6 seconds for AU's prepaid service.)
Both SoftBank and au offer prepaid phones. Details on pricing, phone models, procedure to get them and can be found on their English websites. For e-mail/text-heavy users Softbank is the better choice due to its introduction of "unlimited mail", which gives unlimited e-mail and text messaging at ¥300/month.
The cheaper way is to get a monthly contract, but for this you'll need proof of longer stay (=visa). You can expect to pay around around ¥5000 per month, assuming light calling, but prices are beginning to fall. A cancellation fee may also apply if the contract is terminated early.
If you are only staying for a week to a month, and don't need to make voice calls (or are fine with using Skype for them), and have an unlocked GSM phone, one simple option is to go to a chain electronics store such as BIC Camera and pick up a prepaid data SIM. Voice phone rentals are pretty expensive, and pay-as-you-go phones require that you are a resident, but a prepaid data SIM only requires that you have access to a Japanese phone number to activate it. (Unfortunately, payphones don't work, but in my experience, hotel phones do, or if you have a friend or colleague that you are visiting, they can do the activation for you.)
The last time I visited Japan for a week I made use of an NTT DoCoMo prepaid data SIM in an unlocked Android phone. It worked wonderfully, and was quite cheap (I think it was around $35 for a few GB of transfer good for a whole month).
The easiest way is indeed to come to Japan with a SIM-free device and getting a data SIM.
The best deal I found when visiting for 3 months back in March '14 was ordering an OCN SIM from Amazon JP (http://www.amazon.co.jp/dp/B00EQ12AYS - had same-day shipping option and an additional discount when I was there). I got mine shipped to my hotel.
Once you get the SIM, you register with its ID on the OCN website, choose your preferred data package, etc. and provide an international credit card. Once that's done you're immediately good to go.
I went for a 2GB/mo package for less than $10/mo. This was by far the best deal available in Japan at the time, and it's good for both long and short visits. Additionally, OCN provides their service over the NTT network, so you'll get great service everywhere. When you leave Japan, simply cancel the service on the website, and (oddly enough...) send the SIM back to OCN via post.