AT&T 5G customers will be the first U.S. mobile customers to have the ability to access 5G in Japan through an international roaming agreement with NTT DOCOMO, Inc. and by using a 5G roam-capable device – the first of which will become available on the AT&T network this week.

The agreement delivers on AT&T’s commitment to keeping its customers connected and providing them with access to 5G – at home and around the globe – as capable devices become available.  However, this agreement is only for 5G NSA which uses an LTE anchor/core for all non-RAN related functions.

“As a longtime industry leader providing global connectivity, we’re evolving the breadth and depth of our global coverage with 5G,” said Susan A. Johnson, executive vice president – Global Connections & Supply Chain, AT&T. “This marks a significant milestone for AT&T and our customers.”

AT&T customers on a wireless plan that includes access to 5G in the U.S. will be able to access 5G in Japan through NTT DOCOMO, Inc., when they use a 5G roam-capable device.

But what are those 5G roam-capable devices and when will they be available?  They will surely be based on 3GPP Release 15 5GNR for the data plane, and 4G LTE for everything else, e.g. signaling, network management, security, 4G core/EPC, etc.  Hence, this arrangement might be called “5G NSA roaming with a LTE core network/EPC.”  5G SA roaming will be much more complicated as there is no standard for 5G core network and all the “cloud native” functions (like network slicing and virtualization) it will support.

“We’re excited to launch 5G roaming in Japan on NTT DOCOMO, Inc.’s network because of what it means for our customers,” said JR Wilson, vice president – Tower Strategy & Roaming, AT&T. “Our teams never stop innovating, developing and deploying the latest technology to provide our customers with access to a next-generation network – at home and abroad.”

AT&T claims they have historically been a leader in global roaming. So, while the company continues innovating to enable customers with compatible devices to access 5G internationally, those with LTE devices can still expect the same great roaming coverage they’re used to while traveling.

NTT DOCOMO is the first mobile operator in Japan to offer an inbound 5G roaming service.  Going forward, DOCOMO plans to expand its inbound 5G roaming service with mobile operators around the globe.  Again, that will surely be for 5G NSA service.

https://www.prnewswire.com/news-releases/att-is-first-to-enable-5g-roaming-for-us-customers-in-japan-301130191.html