This is a great question we get asked a lot. I have 2 things for you. You'll wanna use our International Plans | Traveling Abroad without Roaming Fees | T-Mobile page to find the prices for using the service while you're roaming. You can search the country and it'll show you what you'll pay exactly. In your case, Germany is gonna be $.20/min. For Wi-Fi, it'll work a bit differently. You if you're using Wi-fi calling while roaming, calls to US numbers are free. You can see this and more information if you take a look at our Wi-Fi Calling from T-Mobile page.
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