The iOS Region Setting and Apple Pay are linked together in interesting ways that has changed with iOS versions. Up through iOS 10, devices needed to have the region match the country they wanted to add and use cards in: iPhone had to be set to Japan to add and use Japanese credit cards in Apple Pay, and so on.
iOS 11 through iOS 14
This changed in iOS 11 with global FeliCa iPhone and NFC switching. Region setting only needed to be changed to add a card for any particular country and had nothing to do with using it. This is because Apple Pay Wallet displays card options that match the Region setting, it acts like a filter that removes outside clutter. The add card animation cycle shows what’s available:
After adding a card, the Region setting can be anything, as Apple Pay ignores it and takes care of the rest. Many inbound users don’t realize this and have avoided adding Suica to Apple Pay under the misconception that the iPhone/Apple Watch Region has to be set to Japan to use it.
Wallet behavior is the same in iOS 12, even with the iOS 12.2 UI tweaks, but the region setting can be ignored when adding cards to Apple Pay with an app like Suica. Another small change from iOS 11 is that if you have a Suica card deleted from Wallet that is parked on Apple Pay iCloud, Wallet will show you the Add Suica option no matter what the iPhone Region setting is. It’s a nice touch and reminder in case you ever forgot you had one.
Wallet location based prompts for adding Suica and PASMO iOS 13 and iOS 14. Prompt appear under the following conditions: (1) iPhone location is Japan, (2) the Apple ID account has never added a Suica or PASMO to Wallet. Suica and PASMO are then added without changing the device region.
iOS 15 revamped the Wallet add card UI considerably. Transit cards are now region free, anybody can create new transit cards. Add Suica or PASMO regardless of your device setting. See Suica • PASMO Guide for details. There is also a new ‘Previous Cards’ category for quickly re-adding cards, keys and ID that were removed from Wallet but are saved on iCloud. Some options such as adding nanaco and WAON e-Money cards and Driver’s License ID in Wallet are still region-setting dependent.