After debuting at retail stores around the country on Oct. 20, Apple Pay is now headed to baseball's biggest stage. Apple's mobile payments system will be supported at both stadiums hosting this year's MLB World Series, which will see the San Francisco Giants take on the Kansas City Royals.

Starting with today's game (Oct. 21) at Ewing M. Kauffman Stadium in Kansas City, baseball fans will be able to buy some peanuts and cracker jacks using just their iPhone 6 or 6 Plus via Apple Pay. The same goes for San Francisco's AT&T Park, making the two facilities the first pro sports stadiums to utilize Apple's mobile payments system. Both stadiums' point-of-sale systems are powered by MasterCard's Digital Enablement Service, which supports other forms of NFC payments aside from Apple Pay.

MORE: Apple Pay: Where You Can (and Can't) Use it

Even when the 2014 World Series wraps up, MLB's support of Apple Pay will continue. According to Forbes, you'll be able to use Apple Pay within the MLB.com At the Ballpark app to buy tickets for next year's season once they go on sale in November. The current version of At the Ballpark allows fans to order concessions from their seats, a feature that seems perfectly suited to the instantly authorized payments made possible by Apple Pay.

Available now as part of Apple's iOS 8.1 update, Apple Pay lets you store payment card information to your iPhone 6 or 6 Plus and make NFC payments with your phone instead of pulling out your wallet. The feature is supported at a handful of popular locations, including American Eagle, Toys "R" Us, Nike, Duane Reade, Walgreens, and Whole Foods, with more retailers like Free People and Urban Outfitters jumping aboard by the end of the year.

Mike Andronico is an Associate Editor at Tom's Guide. Follow Mike @MikeAndronico and onGoogle+. Follow us @TomsGuide, on Facebook and on Google+