For a long stay in Japan having a phone number is quite necessary, especially if you intend to work or just open a bank account at a Japanese bank.
It is also highly recommended for short-term visitors as it makes it a lot easier to get around the country, to know which trains to take or to find your restaurants or bars of choice. It`s not too expensive to buy a prepaid Sim for a period of 7, 15 or 30 days.
These prepaid Sim cards can be purchased at the airport or in a big electronics department store like the Bic Camera, yodobahi camera, etc. You will only need a unlocked mobile device that works in the Japanese network and a little patience to carry out the installation.
For those who wish to contract a telephone line for a longer period, there are a few large companies that control most of the sector. These big companies (NTT DoCoMo, Softbank and AU) offer the best services and the best mobiles, but also the most expensive fares and the longest-term contracts.
On the other hand are Mobile Virtual Network Operators (MVNO) which is an operator that rents to one of the large (usually NTT DoCoMo) the use of a small part of their network. They offer contracts more attractive than the big companies in exchange for losing some quality in the service. Most of the time they work perfectly, but some friends talk about a big drop in the speed of connection and even loss of coverage on the train during certain times during rush hour.
The only requirement to sign a contract with these companies is that you have your residence card with the registration on the front. You will also need your passport and your credit / debit card.
As the offers of these companies are constantly evolving, we are going to list a few of these operators for you to choose from: