You can add it using your account in the au PAY app.
Please see below for detailed instructions.
Launch the au PAY app.
Tap on "Account" [アカウント].
Tap on "Settings" [設定] for Apple Pay.
Tap on "au PAY Prepaid Card" [au PAY プリペイドカード].
Enter your au ID password and tap on [OK].
Tap on "Next" [次へ].
Tap on "Set up Apple Pay" [Apple Payを設定].
Tap on "Continue" [続ける].
The au PAY prepaid card information linked to the logged-in au ID will be displayed.
Please verify that the information is correct, then tap on "Next" [次へ].
Wait for the screen to switch.
Review the terms of use and tap on "Agree" [同意する].
Tap on "Next" [次へ].
Tap on "Done" [完了].
Return to the home screen and tap on the "Wallet app".
If the au PAY prepaid card has been added, the registration is complete.
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