For people planning on visiting Japan, Japanese companies offer a lot of prepaid SIM card services with many plans.
However, as the plans are many and separated, you may be puzzled on which one is the best for your itinerary.

We provides you a list of all of the prepaid SIM card services available for getting around Japan.
The list also has their details (data capacity, period, price, and more) so that you now can see them all in one place and compare with the others easily.
Along with it, we also have pages on each service's details.

Find the best prepaid SIM card, and enjoy your wonderful experience in Japan.

NTTDoCoMo has the largest network coverage, and almost all of the prepaid SIM card services in Japan are based on their network.

NTTDoCoMo's 3G (the third generation) network is called FOMA, Freedom of Mobile Multimedia Access.
FOMA uses the 800 MHz band in rural areas while it uses the 2100 MHz band in metropolitan areas (1700 MHz band in a few areas).

However, the 800 and 1700 MHz bands are exclusively assigned to Japan.
So, if you have the 3G network with the 2100 MHz alone, you practically can connect to the internet only in major cities.

NTTDoCoMo also offers 4G (LTE) network under the service name of Xi, having a wide range of frequency bands: 700, 800, 1500, 1800 and 2100 MHz.
Some of the frequency bands are also used in countries other than Japan, however, the 1800 MHz, one of the most usual bands in the world, is available only in the following major cities: Nagoya, Tokyo, and Osaka.

As you have seen above, a usable frequency can vary from place to place, so, its highly recommended to check which band do you need for the area you want to go and which band is your device compatible with before you actually visit Japan.

Also, you have to make sure that your device must be unlocked (sim lock free)
and must support one of the following frequencies:

Pick up Rental Wi-Fi

LightPocket Rental WiFi

LightPocket is a rental service for mobile WiFi routers and Data SIM card that can be used when traveling around Japan. They can deliver to your hotel or you can pick it up at the airport. Choose the plan that best suits the period of your stay! They offer reliable, reasonably priced services for international students and expats to Japan.

Official Site

Japan Rental WiFi list

Since 2006 the "Mobile Phone Improper Use Prevention Act" requires anyone who intends to buy a voice-call-capable SIM card (prepaid or postpaid) to show a proper identification which indicates that he/she has a residential (permanent) address in Japan. A hotel address is not sufficient for this purpose.
All foreigners must have an alien registration to purchase a voice SIM.
As a tourist without a visa which permits to stay for more than 90 days, you won't get one. So you cannot obtain any local cellphone SIM with a voice-call, under your name, period.