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IS Flat

A flat rate system for enjoying high-bandwidth content with a monthly charge of ¥5,200

Flat rate ¥5,200/month Application Required


The packet communications flat-rate service that allows you to enjoy even large-volume content as much as you like. Domestic use of au Wi-Fi SPOTs is also free.

  • Smartphone-only data communication does not exceed ¥5,200/month however much you use.
  • Maximum rate is ¥5,700/month (for WIN/iida) even when you use the PC site viewer
  • Maximum rate is ¥9,900/month when connecting a mobile PC, PDA, car navigation system or other devices

Smartphone-only communication

Basic charge ¥5,200/month
Subscribers can use limitless smartphone-only communication by paying a flat rate.
  • *This service is only available for CDMA 1X WIN.
  • *IS Flat is not applicable to packet communication charges incurred outside of Japan. "Overseas Double-Teigaku" will be available as discount service for overseas packet communication from March 2011. Please visit the URL for "Overseas Double-Teigaku" for a list of the countries where this service is available.

Overseas Double-Teigaku

  • *If you are subscribed to IS Flat, the free calls of this rate plan are not applied to your packet communication charges.
  • *This service is not available in combination with other flat-rate packet communication charge services, including the Double-Teigaku discounts.
Image: IS Flat
  • [1]Applicable services include EZweb and EZ WIN e-mails when using WIN or iida.

Communication using devices other than smartphones

Packet communication charge ¥0.025/packet
Max rate
  • *Price in ( ) is a charge added to the flat rate
EZweb/E-mail [2] ¥5,200/month
(+ ¥0)
PC site viewer [2] ¥5,700/month
(+ ¥500)
Mobile data communication [2]
(only for compatible models)
(+ ¥4,700)
  • [2]When using an au mobile phone by swapping in an au IC card. However, mobile data communication is available with IS02.


If you are using a +WiMAX device and the amount of 3G communications used in less than a month exceeds
5GB, a limit will be placed on the communications speed used for 3G communications until the end of that month.

Eligible models

  • 3G Smartphones
  • iPhone 4S

Service Period

If you are Applicationing for this service along with a new subscription, this service is applicable from the date of subscription (flat rate and free communication are prorated). If you are using IS series, WIN or iida (hereafter "CDMA 1X WIN") and changing your flat-rate packet communication charge service without changing the system, the new service is applied from the month following the month of subscription to the service (excluding changes from "IS Flat" to "Plan E Simple <not using IS Flat>").

If you are Applicationing for system change to CDMA 1X WIN, this service is applicable from the date of system change (flat rate and free communication are prorated). The discount service for packet communication charge subscribed to with the previous system is applied until the day preceding the system change date (flat rate and free communication are prorated).

If you are adding a packet communication charge discount service under conditions not mentioned above, you can select either the subscription month or the month following the subscription month as the month from when this service is applied. If the application for the discount service is made in the same month as a new subscription or system change, flat rate and free communication are prorated. Otherwise, flat rate and free communication are applied in full.

When you are changing or adding a mobile phone model upon a new purchase, if you are Applicationing for a flat-rate packet communication charge service at the same time you are changing your plan from "Plan F (IS) Simple/Plan F (IS)" or "Plan E Simple/Plan E <not using IS Flat>" to another plan with free calls, you can select between starting the service from the following month or from the date of switching/adding lines (flat rate and free communication are prorated).


  • *Free calls of a rate plan is not applicable to packet communication charges.
  • *IS Flat is not fully applicable to the packet communication charge incurred for making the initial setting for "Mobile Suica" provided by JR East.

Restrictions on use

  • If the packet communications charges for usage are high, your line may be temporarily suspended regardless of whether or not you are enrolled in a packet communications flat rate/discount service.
  • To avoid network congestion, a limit will be placed on communications speed for a whole day if you have used more than 3,000,000 packets over the three most recent days (not including the day on which the restriction is applied).

Communications optimization

  • ISNET series packet communications may perform system optimization to improve the display speed of images and the waiting time before video playback begins.

    Image files BMP, jpg, gif, PNG formats
    Video files MPEG, AVI, MOV, FLV, MP4, 3GP, WebM, ASF, WMV formats
    • *HTTPS communications and files with email attachments are not optimized.
    • *Smartphone communications with au.Net are also applicable.
    • *Customers who do not need communication optimization can contact the Customer Center (157) to have optimization cancelled.
    • *Optimization is the compression and conversion of images to the appropriate size for a smartphone screen. Compressed and converted data cannot be restored.

*All of the indicated amounts exclude tax unless otherwise specified.