Costco shoppers can now use Apple Pay to make their purchases across the US. The support applies to all 750 of the bulk retailer’s outlets across the country, and Costco says it’s also planning to enable Apple Pay support at its gas stations.

It’s the latest big breakthrough for Apple in terms of getting major retailers onboard for its mobile payments platform. As TechCrunch points out, it comes on the heels of agreements with 7-Eleven and CVS, with the latter having gone so far as to implement its own mobile payments app in its resistance to Apple Pay. Whereas that system was based on barcode scanning, though, Apple’s solution uses contactless NFC technology and biometric authentication, the convenience of which will probably be appreciated by customers who use it.

The major retailers’ support thus underscores the growing prominence of Apple’s mobile payments platform, which appears to have entered into a new phase of legitimacy as a payment option. It’s still far from mainstream, of course; but a recent report from Loup Ventures estimated that Apple Pay already has 252 million users worldwide, and that it had grown a base of 25 percent of iPhone users a year ago to 31 percent now. That points to a solid upward trajectory, which could be accelerated as more partners and supporters like Costco get onboard.

Sources: TechCrunch, CNET