U.S. wireless carrier AT&T on Monday announced it has launched Voice-over-LTE (VoLTE) roaming in Japan for its customers courtesy of a deal with NTT DoCoMo.

According to AT&T, customers traveling in Japan with compatible devices will now be able to use HD voice services when calling other AT&T customers with VoLTE service. In addition to enabling HD voice services, AT&T indicated VoLTE allows customers to simultaneously talk and surf the web.

AT&T said the service will be enabled via an agreement with Japan’s largest telecommunications company, NTT DoCoMo. AT&T reported it is the first U.S. carrier to offer VoLTE to customers traveling in Japan.

Verizon in June of last year signed an agreement with Japanese carrier KDDI to offer VoLTE services to KDDI customers visiting the United States. Though that agreement did not initially include VoLTE roaming for Verizon customers in Japan, Verizon said it was testing VoLTE roaming with “multiple carriers” and expected to offer VoLTE and HD voice roaming in Japan in late 2016. It seems, however, AT&T got the jump on that launch.

AT&T first launched VoLTE services on its network in select markets back in May 2014, and expanded service to a number of new markets late that same year.

According to IHS, the number of VoLTE users is expected to ramp to 1 billion by 2020. Ericsson predicted that figure will grow to hit 3.3 billion subscriptions and 60 percent of all global LTE subscriptions by the end of 2022.