After receiving a waiver from the FCC in November, Verizon announced it will roll out Wi-Fi calling to its first customers beginning tomorrow.

According to a Friday post on Verizon’s news blog, Verizon customers with Advanced Calling will be able to utilize Wi-Fi calling starting Tuesday. The feature will initially only be available to users on the Samsung Galaxy S6 and S6 Edge through a software update.

Calls made on a Wi-Fi connection to a domestic number are free, the company said, but those made to foreign numbers will be billed at international long distance rates.

Verizon said Wi-Fi calling will become available to other Android and iOS users through software updated expected early next year.

Tuesday’s launch of Wi-Fi calling will make Verizon the last of the four major U.S. carriers to offer the feature to customers. In October, AT&T went live with Wi-Fi calling after lobbying for a TTY waiver from the FCC.

T-Mobile was the first to offer Wi-Fi calling to its Android users in 2007, and made the service available to iPhone customers with iOS 8 within the last year. In April of this year, Sprint became the second major carrier to offer Wi-Fi calling to users of the iPhone 6, iPhone 6 Plus, iPhone 5c and iPhone 5s.

AT&T has previously accused the FCC of playing favorites in allowing the other carriers to retroactively apply for the waivers after deploying the service without them.