Apple pay and data connection requirement?

[sevimli]

Today couldn't use the apple pay at walgreens, later i realized my cellular data was off.

I have a limited data package so I need to turn off my cellular data quite often within a work day, I had no idea that it would affect the apple pay process.

What does apple pay need internet connection for?

 

[duaneu]

It doesn't need a data connection. It just needs to connect to the POS terminal in the store via NFC.