Flat-rate Data (Mobile phone)

This is a flat rate data services that can be combined with Unlimited Calling Plan S (Mobile phone) or Unlimited Calling Plan (Mobile phone).

Data quantity

Monthly charge

Unlimited Calling Plan S
(Mobile phone)

Unlimited Calling Plan
(Mobile phone)

Flat-rate Data 1
(Mobile phone)(1GB)



Flat-rate Data 2
(Mobile phone)(2GB)



Flat-rate Data 3
(Mobile phone)(3GB)


Flat-rate Data 5
(Mobile phone)(5GB)


Flat-rate Data 8
(Mobile phone)(8GB)



Flat-rate Data 10
(Mobile phone)(10GB)



Flat-rate Data 13
(Mobile phone)(13GB)



  • As of September 14, 2016, new applications (including changing contracts) for Flat-rate Data 8/10/13(Mobile phone) are no longer accepted. Customers who are currently using the plan may continue to use it.
  • The unused data amount can be carried over to the next month.

    For Flat-rate Data 5/8/10/13(Mobile phone) the unused data amount in a month can be carried over and used by the end of the next month.All of the unused data amount can be carried over, eliminating waste.

  • You can purchase data quantity starting from 0.5GB using the Data Charge service when needed.

    You can purchase as much data quantity as you need (in 0.5GB or 1GB units) in real time when you need it. You do not need to worry even if you use a lot of data.

  • Data Present allows you to give purchased data to friends and family.

    Give newly purchased data to friends and family. The person who receives the Data Present can increase the data amount they use by the amount given.

  • Data Gift allows family members to give data quantities to each other without waste.

    The Data Gift service allows family members to give the monthly data quantities (in 0.5GB units) to each other in real time at no additional charge, ensuring that extra data quantities are used without going to waste.

  • Long Term Hospitality Data Gift gives long-term customers extra data amounts.

    Long-term au customers will receive an extra data amount once every 3 months according to the au contract period (4 years and over) and subscribed Flat-rate Data service.

Eligible models

  • 4G LTE Feature Phone
  • mamorino Watch
  • This service is not supported on AQUOS K SHF31.


Universal service system

In accordance with the launch of the "Universal Service System", KDDI has begun imposing a "Universal Service Fee" on customers who signed contracts with us for their portion of usage since January, 2007.
See below for the details.


[Flat-rate Data]

  • For Flat-rate Data 1/2/3/5/8/10/13(Mobile phone) users, when World Flat-rate Data is used overseas, the communications charge consumes the monthly data amount of the domestic Flat-rate Data service. If you are using Two-step data flat for Overseas, you will be charged for data communications used overseas. It is not included in the domestic monthly data amount.

[Application of Charges]

  • If applying when making a new subscription or switching models, the rate plan and Flat-rate Data service become applicable from the date of subscription or the date of switching models (the basic charge/Flat-rate data charge is prorated). If changing the contract or switching to a model you bring to a shop, the service becomes applicable from the month following the month of the change or switch. If you cancel in the middle of a month, the rate plan and Flat-rate Data service charges are not prorated and the flat rate is incurred (If not subscribed to 2-year contract or 2-year contract(No automatic renewal), the basic charge is prorated.).
  • Check for other costs arising from the contract at the store.

[Restrictions of communication speed]

  • If the total amount of communications of the month exceeds the data quantity for that month, the maximum communications speed for sending and receiving until the end of that month will be 128 kbps. (The communications speed constraint will be removed on the first day of the following month.) If you apply for the Extra Option, the communications speed constraint does not apply. Data quantities purchased with Data Charge can be used without any communications speed constraint.
  • To avoid network congestion, a limit may be placed on the communication speed for a whole day if the total amount of communication used exceeds 6GB over the three most recent days (not including the day on which the restriction is applied). The restricted speed will differ depending on data traffic conditions.

    (The restriction applies regardless of the remaining data amount.)

  • Regardless of whether you are subscribed to a Flat-rate Data service, your line may be temporarily suspended if the cost of the packet communications you use becomes high.

[Communication amount notification]

<When using Flat-rate Data>

  • Customers are notified via SMS (C mail) when the remaining amount of their monthly data amount drops below 10% or reaches 0% during the current month.

<When using Data Charge>

  • Customers whose total monthly data quantity and purchased data quantity for a given month is 5%,1% or lower will be notified by email to the mail address registered to the au ID.
  • The actual amount charged is calculated using the tax amount calculated from the total amount of the individual tax-excluded charges, and therefore may differ from the total of the individual tax-included charges.
  • By phoneOpen 9:00 – 20:00

    • English

      0120-959-472(Toll Free)

    • Portuguese

      0120-959-473(Toll Free)

    • Chinese

      0120-959-476(Toll Free)

    • Korean

      0120-959-478(Toll Free)

    • Tagalog

      0120-933-952(Toll Free)

    • Vietnamese

      0120-933-961(Toll Free)

    • Japanese
      about au mobile services

      157(Toll Free)from au phones

      0077-7-111(Toll Free)

      about Internet services
      Contract / Fee / Billing

      0077-7084(Toll Free)

      Connection setting / failure

      0077-777(Toll Free)