Mobile Phone in Japan (2) What Is the Kakuyasu SIM Card in Japan?

Many people may know that there is  a kind of SIM card called Kakuyasu SIM in Japan, of which the monthly fee will be relatively cheaper, and the application is not so troublesome. In recent years, DOCOMO, AU and SOFTBANK have also launched ahamo, povo and linemo packages with cheaper rates. In this blog, we will introduce you to information about the cheap cell phone packages.

What is Kakuyasu Card

If you are new to the Japanese lifestyle, you may not have heard of a “kakuyasu card”. The Japanese word “kakuyasu”, means extra cheap, very cheap. Therefore, the term “kakuyasu SIM card” refers to a SIM card with a very low monthly fee.

How cheap is it?

According to statistics, the average monthly fee for a kakuyasu SIM card starts at around 800 yen (880 yen with tax), and with data communication and “free call in 10 minutes” package, it may only cost 1500 yen in total. The plans of the big companies we will mention below have an average monthly cost of 5,000-7,000 yen. At half or even a quarter of the price, it’s no wonder it’s called a kakuyasu card.

Benefits of the kakuyasu Card


The biggest advantage of kakuyasu SIM card is of course its cheapness.

Instead of setting up their own equipment, kakuyasu SIM card usually leases the networks of the three major Japanese cell phone companies, SOFTBANK, DOCOMO, and AU, to provide services. Since they don’t have to build their own network, the cost of providing services is reduced, and the fees are much cheaper.

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Although kakuyasu SIM card companies don’t have their own communication network, we don’t have to worry too much about the signal of the kakuyasu SIM card. Since the network is leased from large companies, kakuyasu SIM card can be used wherever the three major communication companies’ networks are available.

Easy to apply

When you first arrive in Japan, many people get caught in a logical loop: you need a bank account to get a cell phone number, you need a stable residence to get a bank account, and you need a cell phone number to rent an apartment …… comes back around.

If you give up on the three major phone companies and choose kakuyasu SIM card, you can generally apply successfully if you have a credit card. If you are a student, you can also apply for a daughter card of your parents’ credit card.

Also, in addition to going to a store, more and more kakuyasu SIM cards are available online, so it’s easy to fill out the form online and upload your ID and credit card information.

Disadvantages of the Gean Card

Requires your own phone

When you sign up for a SIM card portal with one of the three major cell phone companies, you often have the option of tying a new phone to the contract. For those who want to replace their phones, it’s a great chance to get a new phone.

However, if you use a kakuyasu SIM card, you can’t tie your phone to the contract, you need to bring your own phone, and your phone needs to be SIM free.
The most important thing is to have a SIM free (unlocked) phone. The good thing is that most of the cell phones nowadays even the three major cell phone companies in Japan have been ordered by the government to provide unlocked phones, so as long as you’re not looking for installment payments, there’s nothing wrong with having a phone for your kakuyasu SIM card, and you can even bring one from your home country to Japan.

Internet may be unstable

Although we mentioned earlier that kakuyasu SIM card companies leases a large company’s network, so the network coverage is not too bad compared to large companies. However, during ruch hour, such as commuting to and from work, or at crowded festivals and interchange stations, the network may give way to the large company’s users, and occasionally the network speed may be slower or temporarily unavailable.

But it is only in extreme cases. Under normal circumstances, there is no inconvenience in using a kakuyasu SIM card for network communications.

No mobile email accounts

If you have a cell phone card from a major company, it usually comes with a free service, which is a cell phone email account. The so-called cell phone mail account is the mail account with the name of cell phone company like “”, “”, “” at the end of @. If you use a kakuyasu SIM card, you will not be able to get such free service.

However, there are many free email addresses that you can apply for. Gmail, Yahoo Mail, etc. are the most popular ones in Japan. If you use these free email addresses, it doesn’t seem to be a problem if you don’t have a mobile email account.

No in-store after-sales support

The other big problem with kakuyasu SIM card is that it may not have in-store after-sales support.
If you have a SIM card from a major company, you can go to a store and get after-sales support for any difficulties you encounter during use.
However, kakuyasu SIM card suppliers rarely have stores in order to reduce their costs.

However, there are often plenty of help and explanation pages on the kakuyasu SIM card website. If you have any questions, you can ask or request help online and get the same level of support that you would get in a store.

Recommended Gean Cards

Below is a list of some of the suppliers of Gyan Card that you can check out on the official website if you are interested.

There is another company that is comparable in price to Kakuyasu SIM, but has built its own network like the Big Three.Rakuten Mobile(楽天モバイル)

the Big Three : top three cell phone companies in Japan

Although this article is mainly for newcomers to Japan to introduce kakuyasu SIM card, but because the three major cell phone communication companies in Japan are mentioned several times, we also split space to tell you about these three cell phone communication companies.

In Japanese, the three major mobile phone communication companies in Japan refers to DOCOMO, AU, and SOFTBANK.

Generally speaking, DOCOMO signal is the best but the most expensive, SOFTBANK is the cheapest, AU between the two. Also, because SOFTBANK’s network calls are free, more international students choose SOFTBANK’s cell phones. Japanese people are more likely to choose DOCOMO.

In the normal package, the average monthly cost of cell phones from the three major companies is about 6000~10000 yen, which may include a basic monthly fee starting from 5000 yen, and then there is a cell phone installment fee starting from 2000 yen. The package includes monthly high-speed data (more commonly 10GB or 20GB per month, but now there are also companies offering unlimited data packages, which are a bit more expensive), and if you buy a call package for about 880 yen, you get a “5 minutes free call” offer. If a voice call is within 5 minutes, the call will be free of charge.

The downside of the three major companies is that the rates are high and the contract is usually tied for 2 years and will automatically renew. If you cancel your contract early, or if you are not in the required time, you may have to pay a high cancellation fee. However, Japan has already started to tackle this bullying clause. At present, the three major companies still charge a penalty fee to cancel the contract, but it has been reduced to about 1,000-3,000 yen to be able to cancel the contract.

In addition, if you buy a cell phone from one of the three major companies, the phone you get is usually a SIM-Locked cell phone, must be tied to the same telecom operator’s SIM card. If you want to use another SIM card, or if you want to keep the phone when you switch to another carrier, you need to apply for unlocking the phone to make it SIM-free.

the top three’s kakuyasu plan

In 2021, with the Japanese government’s further control over cell phone tariffs, all three companies launched their own “kakuyasu SIM”. Although they are also called “Kakuyasu”, the “Kakuyasu plan” of the Big 3 is definitely a bit more expensive compared to the real kakuyasu SIM card companies we mentioned above. However, considering that it is backed by the three major cell phone companies, the signal coverage and communication speed should be much better than the ordinary kakuyasu SIM card, and it is possible to get cell phone mail accounts and other services exclusive to the three major cell phone companies, it should also be cost-effective.

Below is a list of the cheaper cell phone packages offered by the three major cell phone companies. If you are interested, you can take a look.

ahamo (DOCOMO)
Tariff PLAN: Voice Call + 20GB High Speed Traffic 2,970JPY per month
Tariff PLAN: Voice Call + 20GB High Speed Traffic 2,728JPY per month
Mobile PLAN: Voice call + 20GB high speed traffic 2,728JPY per month
mini PLAN: Voice call + 3GB high speed traffic 990JPY per month


  • *Depending on the time of use, there may be speed limitations
  • *Voice calls are based on call length (22 yen/30 seconds)
  • *Online contracting only
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GetAround Japan is your number one travel guide, providing the latest information on visiting and living in Japan, with tips on what to eat, things to do, and places to stay. Whether you're planning for a trip far in the future, or already in Japan in need of some fresh ideas, our archive of posts will help you find the best way to fill your time and get the most out of your travel experience. We provide you updates on serious policies that affect visitors and foreign residents while also keeping things light and fun with articles on quirky trends and pop culture. How do we know how to provide visitors the information they need? Our affiliate company CDJapan Rental provides WIFI and Sim Card rentals to thousands of visitors to Japan every year. In other words, we are constantly in touch with and listening to the voices of our customers, and infuse our blog with the information they ask us for. For inquiries, contact us here Company Information CDJapan Rental (Neowing Corporation) 1-10-15-3F Nihonbashi Horidome Chuo, Tokyo 103-0012, Japan

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