Seven Criteria for Choosing a Mobile Plan That Fits You

The short answer

There is no single best company for everyone when choosing a low-cost SIM, usually offered in Japan by an MVNO, or any other mobile plan. The quickest route is to write down how you use your phone against seven criteria, then check each provider's official information for terms that fit. This article is about Japan's mobile market. It does not compare or rank companies, and covers only points confirmed on the mobile phone portal of Japan's Ministry of Internal Affairs and Communications (MIC).

The seven criteria

MIC gives examples of where reviewing a plan can save money: calling often without an unlimited calling plan, or using far less data than the plan includes. Criteria 1 and 2 are the starting point.

Criterion 3 matters because low-cost SIMs may slow down when networks are busy. For criterion 4, MIC's portal also groups mobile brands by whether they offer in-person support at shops.

Your device and cancellation terms

If you plan to keep your current phone, check criterion 6 first. According to MIC, a phone bought from one of the three major carriers and released on or before September 30, 2021 may be SIM-locked. Even after unlocking, the phone may connect poorly depending on the frequency bands it supports, and MIC suggests checking the new provider's list of devices confirmed to work. An APN setting may also be needed for VoLTE calls.

For criterion 7, also check how the final month is billed, that remaining device installments still have to be paid, and whether payments charged to your phone bill or points will stop being usable. Carrier email addresses can be kept through a paid carrier email portability service, which you apply for with your current carrier.

Reading advertised prices

MIC warns that TV commercials and similar ads often show the lowest price with every discount applied. Check whether the price includes discounts that last only for the first six months or apply only with family members, and check the monthly price after those discounts end.

Write down how you use your phone

1. Monthly data (last 3 months):
2. Calls (often / sometimes / rarely):
3. Use at busy times (lunchtime, commute, etc.):
4. Support (want to ask in a shop / fine doing it online):
5. Family and bundle discounts (current ones):
6. Device (model, where bought, SIM lock, eSIM support):
7. Cancellation terms (fees, installments left, carrier email):

If the service turns out different from what you expected, systems such as initial contract cancellation may apply within eight days of receiving the contract documents. Check MIC's portal and your provider's information for who is covered and on what terms.