Quickest way to launch Wallet when phone is unlocked? The quickest way I know of to launch the wallet app in "tap-to-pay" mode is to: 


lock the phone, 
double-tap the home button,
activate Touch ID


Is there a way to do this without locking the phone first, to make it quicker? 

Double-tap when the phone is unlocked will bring up the app switcher.

Note: This question is for phones with Touch ID, e.g. iPhone 6, iPhone 7
Go to Settings -> Control Center and add Wallet to the active list. Then you can swipe from Control Center and select Wallet any time the phone is unlocked.