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The following provides answers to some of the frequently asked questions about the Prepaid SIM for JAPAN service.

General Information

Q1 What services does Prepaid SIM for JAPAN offer?
A1 This Service provides you with either a 7 or 14 day access to NTT DOCOMO's "LTE" and "FOMA 3G" networks operated within Japan by NTT DOCOMO, INC ("DOCOMO"), and includes 100MB/day of high-speed data with speeds of up to 788Mbps.
It is for data use only, and does not have an option for voice calls or SMS text messages.
Q2 Are there restrictions on mobile data communications?
A2 In order to provide quality service to all Prepaid SIM for JAPAN customers, we place the following restrictions and limitations on using data service.
  • ・The maximum speed available on your device varies depending on the device capability.
  • ・Congestion control may be performed to avoid congested network conditions becoming persistent.
  • ※ Details of bandwidth restrictions and congestion control are subject to change.

Speeds High-speed data allotment Speeds after the daily high-speed data allotment is used
Up to 788Mbps 100MB per day The maximum speeds will be reduced to 200kbps (up/down).
Speeds Up to 788Mbps
High-speed data allotment 100MB per day
Speeds after the daily high-speed data allotment is used The maximum speeds will be reduced to 200kbps (up/down).
Q3 Why are my speeds much slower than the claimed download speeds of up to 788Mbps?
A3 The available speeds specified represent maximum speed capabilities based on technical specifications and are not guaranteed. Actual speeds vary and may be significantly slower depending on the network equipment including your device or network availability.

Visit NTT DOCOMO website  to find the LTE areas with coverage up to 788Mbps downstream.
In LTE areas, service is available at speeds of up to 788Mbps for download and up to 50Mbps for upload.
Customers have access to FOMA 3G network where LTE coverage is unavailable (Even within LTE areas, service may default to FOMA 3G network depending on the signal strength). You receive speeds up to: 14Mbps for download / 5.7Mbps for upload in FOMA High-speed area; 384kbps for download and upload in other FOMA areas. For more details, access to the NTT DOCOMO website  page (in Japanese).
Q4 Can I use a 2G / GSM device?
A4 No, 2G and GSM devices do not work on this service.
Q5 Can I change my data allowance?
A5 No, you cannot change your high-speed data allotment on this service.
The restrictions will be released at midnight tonight, so please wait until then.
Q6 Can I change the size of my SIM card?
A6 You cannot change the size of your SIM card. We do not accept return, exchange or cancellation after purchase of the Prepaid SIM for JAPAN SIM Package. Please make sure you choose the right size for your device before you purchase it.
Please re-purchase the SIM card with appropriate size.
Q7 Where can I use this service?
A7 You can use this service while in "LTE" and "FOMA 3G" areas operated within Japan by NTT DOCOMO. Coverage details can be found on the NTT DOCOMO website  (Japanese only).
Q8 Can I make voice calls or text SMS messages?
A8 This service is for data use only and does not offer voice calling and SMS texting features.
Q9 Can I stream videos?
A9 This service is not suitable for contents or activities that require continuous and large amounts of data, including video streaming.
Q10 Can I use this service outside Japan using International roaming?
A10 No, you cannot use this service outside Japan. International roaming is not available on this service.
Q11 Can I cancel my service while it's still active or extent my service period?
A11 No, you cannot cancel or extend your service.
If you would like to continue using this service, please purchase a new SIM card.
Q12 Can I add more data or SIM cards?
A12 No, those options are not available for this service.
Q13 What kind of devices can I use?
A13 Click here for a list of supported devices.
Please make sure your device is unlocked, supports one of the following frequencies: [LTE] Band (2100MHz), Band 19 (800MHz), Band 21 (1500MHz), Band 3 (1800MHz, limited to the Toumeihan area); [W-CDMA/HSPA (FOMA)] Band 1 (2100MHz), Band 19 (800MHz), AND The only devices that may be used are those that either bear the mark of technical regulations conformity certification (Technical Conformity Mark) indicating, for example, certification of conformance to the technical standard for specific radio equipment, or meet conditions allowing confirmation of their conformance to the technical standard stipulated under Japan's Radio Law (i.e. devices bearing symbols indicating certification of conformance to a technical standard, such as the USA's FCC mark and the European CE Mark).
Q14 Can I let other people use my service?
A14 No, it is not permitted to do it or to resell your service to a third party.
Only the person who has purchased the SIM package is allowed to use this service.
Q15 How soon can I use my data service?
A15 Once you have submitted an activation request and set up your device, the data service will be activated and ready for you to access.
Instructions on activation and device setup come with the SIM package.
Q16 Can I use Internet Tethering?
A16 Yes, but only if your device supports a tethering / personal hotspot feature.
Q17 Can I use the same SIM card across multiple devices?
A17 Yes, you can use it on any device as long as they are compatible to the SIM card.
Q18 What is "Japan connected-free Wi-Fi"?
A18 It is a free WiFi hotspot service by NTT-BP, designed for visitors to Japan, which is found in International airports, Shinkansen train stations, major tourist attractions and popular locations across Japan.

  • ※ Japan connected-free Wi-Fi is operated by NTT Broadband Platform, Inc., not by NTT Communications Corp.
Q19 What is the difference between the two packages: "OCN mobile ONE Prepaid SIM for Visitor" and "Prepaid SIM for Japan"?
A19 The name of the service changed on 11/1/2014.
Packages under the former name can still be used.

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Use / Settings

Q1 I have purchased the Prepaid SIM for JAPAN package, what do I need to do next?
A1 Sign Up for the service
  • 1:Go to the Sign Up page at Open in a new window to activate your SIM card.
  • 2:Follow the steps to enter your SIM card ID number and device serial number printed on the back of the SIM card holder. Complete the customer information fields, and then submit your request.
Setting Up SIM Card
  • 3:Push out the SIM card from the SIM card holder, and then place it in your device.
  • 4:Check the device manual for how to insert the SIM card in your device.
Setting Up Device (See the APN Settings page for details)
  • 5:Go to the APN Settings to configure the APN on your device.
  • 6:Surf the Web.

  • ※Keep the SIM card holder as you may need it when you contact us. If you contact us after activation, please provide us with your NTT Communications customer number (a 10-digit number prefixed with an N) or SIM Phone Number.
Q2 What does it mean by "Sign Up (Activation)"?
A2 It is a process to make your SIM card work on your device.
After you have activated your SIM card, you will need to setup APN on your device to start using the data communication service.
Instructions on activation and the APN configuration are provided in the service manual included in your SIM package.
Q3 Is there expiration for "Sign Up (Activation)"?
A3 The SIM Package has a valid period for activation. Once it has expired, you will not be able to request activation.
Q4 What is "APN"?
A4 An APN (Access Point Name) identifies a network to connect to.
To make your SIM card work on your device, you will need to configure your device with the APN for the mobile data service.
Q5 How do I set up APN?
A5 Instructions on the APN settings are provided in the service manual included in your SIM package and on our website:
Android Devices / iOS Devices
Q6 Do I need to setup MCC/MNC in the APN settings?
A6 You can leave the settings if it is automatically configured. If not, you need to set it up manually using the following values:


Q7 How can I tell if my device conforms to the technical regulations for specified radio equipment under the Radio Law?
A7 For details, please visit  (the Ministry of Internal Affairs and Communications).
Furthermore, the only devices that may be used are those that meet conditions allowing confirmation of their conformance to the technical standard stipulated under Japan's Radio Law (i.e. devices bearing symbols indicating certification of conformance to a technical standard, such as the USA's FCC mark and the European CE Mark).
  • ※Details of the conditions mentioned above can be found here
Q8 How do I configure the APN settings on my Apple device?
A8 Some devices require a configuration profile for the APN settings. You can download the configuration profile HERE, and install it on your device.

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SIM Card

Q1 Do I need to return my SIM card when finished using Prepaid SIM for JAPAN?
A1 All the expired SIM cards must be returned to us at the following address, but please note shipping costs are at your expense.

Return Address:
Sumitomo Warehouse
"OCN SIM Card Collection Dept."

When returning your SIM card after the cancellation process, please be sure NOT to enclose any items other than the SIM card supplied by NTT Communications. If you enclose any other items, they will be disposed of. Any items that we are unable to dispose of will be sent back to you on a Cash on Delivery basis.

Q2 What are Service "Start date" and "End date"?
A2 They are the start date and the end date for the mobile data service.
Regardless of the start day, once you've submitted your activation request, the service will be ready for you to access.
Q3 Where can I find the start day and the end day of my service period?
A3 They will be displayed on the screen after you submit your request on the "Sign Up" page or can be found in the sign up confirmation email sent to your registered email address.

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Q1 What should I do if I lost my SIM card?
A1 We do not accept returns and exchanges once the service is activated, even if your service becomes unavailable as a result of loss / defect / damage of the SIM Card or poor signal reception.
Q2 I haven't received the activation confirmation Email. What should I do?
A2 Please contact the help desk as there is a possibility that your email address was entered incorrectly during registration. When contacting the help desk please inform the operator of the SIM card ID number.

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Help Desk (For "Prepaid SIM for JAPAN" users)*Domestic calls only.

Before sending inquiries, please see FAQ.
  • ◆After Purchase◆
    Technical Support

    Free Dial 0120-047-427

    Business hours: 10:00 - 18:00

    Available 7 days a week, including holidays
    (Unavailable during new year’s holidays)

    *Available in Japanese, English, Chinese, Korean.

Click here for a list of stores.
Before making an inquiry, please read through the FAQ page. Please be careful not to dial a wrong number.