Yes. Using Wi-Fi calling to US numbers is free. Do not use it to call for calling foreign number$.
Does not matter is US number is in NY or London.
I think you'd find this info super helpful:
How Wi-Fi calls and messages are billed
Wi-Fi calls placed to other countries are subject to international long distance rates, based on your international calling feature.
What you're doing
What you're charged on Wi-Fi Calling
Receiving calls and messages
Making a call to a U.S. number
Sending a message to a U.S. number
If you have an unlimited plan (T-Mobile ONE™ or Simple Choice rate™), all incoming calls, all incoming messages, and all outgoing calls and messages to U.S. phone numbers are free while connected to Wi-Fi Calling.
If you have a plan without unlimited calling, calls made over Wi-Fi Calling count against your plan minutes.
For prepaid lines, calls made over Wi-Fi deduct from the plan bucket, just like regular calls.
Making a call to a non-U.S. number
When in the U.S.
Wi-Fi calls placed to other countries are subject to your plan's long distance charges.
When outside the U.S.
If you have a T-Mobile ONE™ or Simple Choice rate™ rate plan:
- From any Simple Global country, calls are $0.20/min (same as cellular).
- From a cruise ship, ferry, and any countries not on the Simple Global list, calls are charged World Class rates.
Yes she will and she can call or text back to U.S. at no charge as long as the phone has the settings correct for WiFi calling. BUT, she can’t rely on getting to use the “free data & texting” when NOT on WiFi (using cellular & roamIng). Coverage appears to be so spotty or actually non existent with Tmobile or their partners. Half the time in major European cities we’ve been unable to use data, and our son is in Australia right now and has yet to be able to send or receive texts or use data if not in WiFi range. And yes, T-Mobile confirmed phone was properly set up during troubleshooting, and just said oh well, maybe not close to a tower. 5 days now in Sydney and Brisbane moving around and not close to any tower? It only works on WiFi even tho set up for cellular and roaming. Finding service very unreliable, so can’t count on it outside of WiFi. The free texting and data in 120 countries is an ad slogan not true.
We have used the "free" roaming for the four or five years since they have had it. In Europe - Italy, Croatia, Germany, Suisse, Austria, Hungary, Romania, (and even were on Ukraine when within 15 miles of its border. Never a problem. Used data mainly for Google Maps driving in some countries. Voice and data all over.
Have also used service in about 6 or 7 other countries.
What phones r u using? What plan?
I agree have been to Europe and Caribbean. Always had data and texting. Data is slower (128K or 256K so streaming won't work well). Since wifi networks are not controlled by T-mobile your experience may vary. Of course, use it when you can. Even in the U.S.A. I do not find it to bee 100%. Restarting phone may help for various reasons.
Do you understand that frequencies vary from country to country around the world and many phones do not have the hardware capabilities to connect with all the channel variations?? You can use www.willmyphonework.net to find out if your phone is compatible with any particular country.