Prepaid means "pre = in advance" and "paid = paid," and refers to payment in advance or in advance.
In fact, there are prepaid SIM cards available, which allow you to purchase a SIM card with a predetermined data capacity and validity without having to sign a contract with a specific carrier.
However, when you hear the term prepaid SIM, you may not be able to imagine what its features are.
In this article, we will introduce in detail the overview of prepaid SIM cards, as well as their advantages and disadvantages and usage scenarios.
In the latter half of the article, we also explain the process for activating a prepaid SIM, so please take a look.
A prepaid SIM is a one-time purchase SIM that can be used without signing a contract with a specific carrier.
With a regular SIM card, you choose a plan from your carrier and sign a contract by presenting identification and a credit card for payment.
On the other hand, prepaid SIMs (data SIMs) are one-time purchases with a set data capacity and validity, so these screenings are not required. (Voice call SIMs require identity verification.)
Prepaid SIM cards can be used just like prepaid cards, without any complicated screening or procedures.
If you don't quite understand what SIM is, please refer to the article below.
Reference: What is a SIM? Understanding the Basics of SIM Cards | povo Library | [Official] povo2.0
Now that you understand the basics of prepaid SIM cards, let's take a look at their specific benefits.
There are various benefits, such as not needing to go through the process of signing a contract with a carrier and being able to choose and purchase the amount of data you want.
As briefly explained above, the biggest advantage of prepaid SIM cards is that they can be used immediately without any carrier screening or procedures.
With a regular SIM card, you will be required to go through an application process, which involves submitting identification to the carrier you plan to use and registering your payment method.
A unique feature of this plan is that you can only proceed with the activation procedure once you have successfully passed the membership screening.
Therefore, it may take several days for your SIM card to arrive.
On the other hand, with a prepaid SIM, you purchase a SIM with a set amount of data and talk time, so once you use it up, your use ends.
Because of this system, there is no need to sign a contract with a carrier or go through an inspection like with a regular SIM card, and you can start using it immediately after purchase.
Prepaid SIM cards have set fees based on the data capacity and validity, such as "2GB: 4,000 yen (3-month expiration date)."
Therefore, the advantage is that you can choose the amount of data you want to use and validity before purchasing.
In addition, once you have used up the data capacity or validity you have purchased, you will basically no longer be able to use the SIM, so you don't have to worry about overuse and high fees.
One of the benefits of prepaid SIM cards is their convenience, as they can be purchased in a variety of places, both online and in stores.
The main places where you can purchase prepaid SIM cards are as follows:
Prepaid SIM cards from some carriers are also sold at convenience stores, which are the most familiar type of brick-and-mortar store.
You can also purchase and pay online on some carriers' official websites or online shopping sites.
Once you have used up the data capacity and validity of a prepaid SIM card, it will generally no longer be usable.
However, there are some types of plans that allow you to continue using your data even if you run out, as long as you upgrade your plan or add more charge within validity.
If you use a prepaid SIM like this, you don't have to worry if you suddenly run out of data.
If you use data frequently on a daily basis, we recommend purchasing a prepaid SIM card that allows you to top up your data from the start.
Prepaid SIM cards are very convenient as they do not require any contracts or cancellation procedures, but there are also some disadvantages that you should be aware of in advance.
When considering purchasing, be sure to consider the disadvantages as well and only make a purchase if you are satisfied with the product.
Although some prepaid SIM cards allow voice calls, they tend to be more fees.
For example, it is not uncommon for a plan with 3GB of data (for 30 days) plus voice calls to fees more than 10,000 yen.
In other words, if you are purchasing a prepaid SIM with voice calling capabilities, you will likely find fees lower if you sign up with a carrier or low-cost SIM.
When considering a prepaid SIM, it is best to think of it as a data SIM.
In addition, if you apply for a SIM card with a phone number, you will need to verify your identity in accordance with the Act on Prevention of Unauthorized Use of Mobile Phones.
If you are having difficulty understanding data SIM cards, please refer to the article below.
Reference: What is a data SIM? Differences from a calling SIM and tips on how to choose one
We have just mentioned that prepaid SIM cards with voice calling capabilities tend to be more expensive, but data SIM cards also tend to be more expensive than regular SIM cards.
For example, it is not uncommon for a low-cost SIM card to be more cost-effective for the same data capacity.
Therefore, if you want to keep fees as low as possible, it is a good idea to consider a low-cost plan from your carrier or a budget SIM card instead of a prepaid SIM card.
As we have previously mentioned, prepaid SIM cards have a predetermined data capacity and validity, such as "2GB: 4,000 yen (3-month expiration date)."
Some prepaid SIM cards allow you to recharge your data capacity within validity, but generally, once you have used up the data you purchased or the expiration date, you will no longer be able to use it.
If you want to use more, you will need to purchase a new prepaid SIM.
Because validity and data capacity are fixed, we recommend that you simulate how much data you usually use before purchasing.
Prepaid SIM cards are generally data SIM cards, with few voice call SIM cards available, and tend to be more expensive than low-fees SIM cards.
So, what kind of scenarios should you consider using it for?
Here, let's consider scenarios in which prepaid SIM cards can be used.
Some people purchase prepaid SIM cards as a stopgap when traveling abroad or returning to Japan temporarily, for short-term use rather than medium- to long-term use.
With a prepaid SIM, you can check the data capacity and validity in advance and purchase it immediately, regardless of whether you are using it domestically or internationally.
If you're in a hurry, you can purchase them at your local convenience store or electronics retailer, so they tend to be very convenient for occasional use.
For example, some people are unable to sign a contract with a carrier for various reasons, such as having unpaid smartphone fees in the past or not having a credit card or bank account.
In cases like the one above, a prepaid SIM card may be an option, as it does not require document screening and does not require contract or cancellation procedures. (This is for data SIM cards; identity verification is required for voice call SIM cards.)
In addition to when you are unable to sign a contract with a carrier for various reasons, it is also useful when you want your children or family members to use a prepaid SIM temporarily.
For example, in recent years, there have been many cases where children have used smartphones and made charges without their parents' knowledge, resulting in high fees.
It is important to make an effort to teach your children and family how to use smartphones properly, but one option is to use a prepaid SIM card to avoid using up too much data just in case.
With a prepaid SIM, you decide how much data you want to use in advance and then purchase it, so once you use up all the data, you can no longer use it.
This will help you avoid situations where you end up paying a large amount for using too much.
Now that you have a better understanding of the advantages and disadvantages of prepaid SIM cards and the situations in which they can be used, let's take a look at the process for activation.
A SIM lock is a state in which a device is locked so that it can only be used with a SIM card from a specific carrier.
There was a time when this system was introduced by major carriers to prevent non-payment of device fees and resale, preventing SIM cards from being used with other carriers.
However, according to the "Guidelines for Ensuring the Smooth Distribution and Use of Mobile Terminal Equipment" (revised in August 2021), devices released after October 1, 2021 will, in principle, be SIM-unlocked.
However, devices released before September 2021 may be SIM-locked, in which case you will not be able to use SIMs from other companies unless you unlock the SIM.
First, check if your smartphone is SIM-locked, and if necessary, unlock it.
Please refer to the following article for how to check and unlock the SIM lock.
Now that you have confirmed the SIM lock, the next thing to do is check the data capacity and validity of the prepaid SIM you plan to purchase.
As a rough guideline, 1GB of data will allow you to view approximately 6,600 web pages and watch approximately 30 minutes of HD YouTube videos.
Consider purchasing a plan by simulating how much data you normally use.
If you would like to know more about the data capacity that is right for you, please refer to the article below.
Additionally, prepaid SIM cards have validity.
If you plan to use a prepaid SIM card on a regular basis, we recommend choosing a flexible expiration date to prepare for unforeseen circumstances.
If you plan to use it for a short visit, such as returning to Japan temporarily or traveling abroad, please consider the length of your stay.
When purchasing a prepaid SIM card, be sure to pay attention to the size of the SIM card.
| SIM card types | size |
|---|---|
| Standard SIM | 25×15mm |
| microSIM | 15×12mm |
| nanoSIM | 12.3×8.8mm |
For example, there are three common SIM card sizes listed above, with nanoSIM being the most common at present.
If the SIM card you plan to purchase is a nanoSIM, then of course your smartphone must also be nanoSIM compatible in order to use the SIM card itself.
For this reason, it's a good idea to check in advance which SIM card size your smartphone will support.
Then, try purchasing a prepaid SIM card that matches the card size that will fit your smartphone.
Please check the official website of the prepaid SIM to make sure that your smartphone is a "device that has been confirmed to work."
Reference: What are the sizes and types of SIM cards? Things to be aware of when changing the size!
After checking the data capacity and validity of the prepaid SIM and purchasing it, you can proceed with the activation procedure.
The activation procedure varies depending on the company selling the prepaid SIM, and can be done by phone or using a dedicated app.
First, follow the instructions that come with the prepaid SIM you purchased to complete the activation procedure.
Once you receive your prepaid SIM card, remove it from the card holder and insert it into your smartphone.
The method for inserting the SIM card differs depending on the model, such as iPhone or Android.
For iPhones, remove the SIM card tray by inserting a paper clip or the pin included with your iPhone into the small hole at the bottom of the tray.
Then, pay attention to the orientation of the prepaid SIM card you have and insert it into the tray.
The location of the SIM tray varies depending on the iPhone model, so please check Apple's official website for details. (※1)
*1: Reference: "Removing/replacing the SIM card on your iPhone"
For more information on how to change your SIM card, please refer to the following article:
Prepaid SIM cards are convenient because they can be activated without signing a contract, but they tend to be more expensive than carrier or low-cost SIM cards when you consider the data capacity and expiration date.
On the other hand, while you cannot sign a contract without going through the same process as with prepaid SIMs, there are also low-cost SIM plans available that are easy to start and offer even lower fees for limited use cases.
With au 's online-only brand "povo2.0" (*2), all procedures can be completed online, meaning you can receive your SIM card as soon as the next day after applying (*3).
The basic fees is 0 yen (*4), and you can purchase the amount of data you need when you need it. You can also use it for validity Topping such as "Unlimited data (*5) 24 hours tax included 330 yen including tax," Data Top-up" 1GB/7 days for 390 yen including tax included," and "3GB/30 days for 990 yen including tax included."
Another benefit is that you can prevent excessive data usage because you purchase a set amount of data each time.
Please also consider povo2.0, which allows for spot use at lower fees.
*2: As this is an online-only plan, all procedures and support will be handled online. Please contact us via the povo2.0 app or official website.
*3: For customers applying for a SIM card : 9:30 AM to 8:00 PM: You can start using the service immediately after completing the procedure. 8:00 PM to 9:30 AM the next day: You can start using the service sequentially from 9:30 AM the next day after completing the procedure. *Shipping and delivery may be delayed depending on the delivery area and the number of applications.
4: ・If you do not purchase Topping for more than 180 days, your usage may be suspended or your contract may be terminated. When 0 yen and 0 GB, the maximum sending/receiving speed is 128 kbps. For Data Only】 ・Initial purchase of Topping is required at the time of subscription. 【For Calls＋Data】 ・Domestic calls: tax included 22 yen/30 seconds Some calling rates, such as calls to satellite phones, may differ. See here for details. In addition, designated calling rates will be charged for calls to phone numbers set by other companies to fees. Sending domestic SMS: tax included 3.3 yen/text (up to 70 characters) Receiving: Free Up to 670 full-width characters can be sent depending on the model. However, up to 134 characters will be charged for two SMS, and after that, one SMS will be charged for every 67 characters.
※5：ネットワークの混雑時や動画・クラウドゲームなどの利用時に通信速度を制限する場合があります。
Reference: "povo2.0 Plan Details"
