Discover was noticeably absent when Apple Pay launched last fall, but the credit card company is finally on board with mobile payments--or it will be soon.

Apple Pay UK launch date rumours

This fall, Discover card users will be able to use Apple Pay at participating stores and in apps with the iPhone 6 and 6 Plus, Apple Watch, iPad Air 2, and iPad mini 3. The process of adding, authenticating, and using a Discover card with Apple Pay is the same as with cards from other financial institutions (check out our guide here).

It's unclear exactly why Discover decided to wait a whole year to support Apple Pay when American Express, MasterCard, and Visa signed on to support Apple's payment service at launch. Discover CEO David Nelms said at November's Money 20/20 conference that "Apple Pay is important" to the company, but at the time he had no definite information to share on when Discover would support the service.

According to financial blog The Street, the delay might have been related to the one-time security tokens Apple requires financial institutions to create so that no real card numbers are exposed in the event of a merchant breach.

The Associated Press noted that Discover customers have been complaining about the lack of Apple Pay support for months, so the announcement is a welcome one for both Discover users and Apple--the Cupertino company now has all of the major U.S. financial institutions on board as it prepares to roll out Apple Pay internationally this year.