You can change your default Apple Pay cardYou can change your default payment method in Apple Pay for Apple Watch. Here's how to do it.
Apple Pay provides a convenient way to make purchases on iPhone and Apple Watch when out and about (or in the comfort of your home) without needing a physical debit or credit card. You can add as many virtual cards to your Apple Pay as you want. By default, the first card you add is your default. You can change the default card with ease.
How to change the default method on Apple Watch
How to change the default card on iPhone
How to change the default method on Apple Watch
To change the default Apple Pay payment method on Apple Watch:
Open the Apple Watch app on your iPhone.
Scroll down and tap Wallet & Apple Pay.
Tap Default Card under Transaction Defaults.
Select your card.
How to change the default card on iPhone
For your convenience, here's how to change your default Apple Pay card on your iPhone (or iPad) also:
Open the Settings app on your iPhone.
Tap Wallet & Apple...
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You can change your default Apple Pay card