There have been quite a few of you asking questions about T-Mobile’s new Wi-Fi unlimited calling feature and how it might affect international usage and roaming. We’ve managed to get a hold of the above screen shot which nails down exactly what the conditions are for international usage and how such calls are billed.

1. Calls made from the US to international numbers are subject to international rates
2. Calls made from outside the US to US numbers are NOT charged roaming
3. Calls made from outside the US to international numbers are subject to international rates but not charged roaming

As of 5/13 Wi-Fi calls placed on Wi-Fi calling compatible handsets are no longer charged minutes so long as the customer is an Even More or Even More plus postpaid rate plan. Since this screenshot is dated May 23rd and therefore after the new rate plans have launched we’ll take a guess and say this is also available on those rate plans as well.