On your Apple Watch, you can use a supported transit card or on your Apple Watch.
Tap Wallet & Apple Pay, then tap Express Mode.
Tap the card you want to use, then enter your Apple Watch passcode.
As you approach a fare gate or board the bus, make sure your Apple Watch is turned on (it doesn’t need to be connected to a network).
Hold your Apple Watch display within a few centimeters of the middle of the contactless reader until you feel a vibration. You see Done and a checkmark on the display.
You can also go to the Apple Watch app on your iPhone, tap My Watch, tap Wallet & Apple Pay, then tap Express Transit Card. Under Payment Cards, tap the card you want to use, then enter the Apple Watch passcode on your watch.