Basically, smartphones purchased under the main brands of docomo, au, and Softbank are "SIM-locked".
If you meet the conditions set by each communication carrier, you can unlock the SIM lock yourself and put your smartphone in a "SIM free" state. This time, let's introduce what happens when you unlock the SIM lock and its advantages / disadvantages.
First, let's briefly introduce what a SIM lock is. Smartphones purchased under the main brands of docomo, au, and Softbank are basically locked, and data communication is not possible even if a SIM card from another telecommunications company is inserted.
This state is expressed as "SIM locked". Since information such as user's contract information and phone number is recorded on the SIM card, if the SIM lock is applied, you can not use it by inserting the SIM of another telecommunications company and making a call.
[Reference] Is it necessary to unlock LINE MOBILE SIM?
You can easily unlock the SIM lock on your smartphone by yourself if you meet the conditions. The conditions and methods for unlocking are listed on the website of each communication carrier, so let's check them.
In addition, if it is difficult to unlock the SIM online, you can do it at the store of each communication carrier. However, please note that a handling fee of 3,300 yen will be charged if you carry out the SIM unlocking procedure at the store.
The advantage of unlocking the SIM lock is that you will be able to perform data communication even if you insert another company's SIM card into a smartphone purchased from a communication carrier. Each carrier can make a contract for only the line separately from the smartphone, so it is convenient when you want to switch the line to another company with the current smartphone.
Also, when you switch to an MVNO (cheap SIM) contract instead of a telecommunications carrier, you may be able to use your current smartphone as is, so it is recommended to unlock the SIM.
However, depending on the smartphone model, it may not be compatible with the frequency bands provided by each communication carrier, and communication may become unstable depending on the location.
You can check the frequency bands provided by each communication carrier and the frequency bands that the terminal supports from each website, so it is a good idea to check before switching the line contract.
If you unlock the SIM, basically there is no big disadvantage. For example, even after unlocking the SIM lock of smartphones purchased under the main brands of docomo, au, and Softbank, repairs will be handled at each counter.
However, there is no operation check or operation guarantee when using a SIM card other than the communication carrier from which the smartphone was purchased. In addition, there is no guarantee that the data saved in the mobile phone will be changed or lost when the SIM lock is unlocked.
Since the device is not guaranteed, it is a good idea to create a backup yourself before unlocking the SIM lock.
[Reference] Docomo SIM unlock
[Reference] Procedure for unlocking au SIM
[Reference] Please tell me about Softbank "SIM Unlock".
Therefore, if you purchase a smartphone after October 2021, you will be able to purchase the device in a SIM-free state from the time of purchase.
However, if it cannot be confirmed that there is a low risk of non-payment such as installment payments, other alternative means that have a lower effect of restricting user rights and competition will prevent non-payment of installment payments. If it is recognized that it is difficult to do so, the setting of SIM lock may be permitted as an exception.
In this case as well, if the total amount of the terminal price is paid later, or if the purchaser responds to credit confirmation measures and the result is confirmed to be appropriate, there is no procedure for the user. are also required to unlock the SIM lock.
In other words, if you make sure to pay the terminal fee and set the monthly payment to a credit card, in principle you will be able to purchase a terminal that is not SIM locked.
[Reference] Ministry of Internal Affairs and Communications Guidelines for ensuring smooth distribution and use of mobile terminal equipment
* Data is based on editorial research as of early July 2021. *Although every effort has been made to ensure the accuracy of the information, we do not guarantee the completeness or accuracy of the content. * Please use the product at your own risk.
Text / Fumihiko Sato