For adding international data pass for unlimited high speed data and unlimited calling, Please allow me to provide you the steps using your T-Mobile app.  


10 days for $35 & 30days for $50


1 Open the app and tap Account.
2 Tap the picture of the phone.
3 Tap Plan details tab at the top.
4 Tap Manage data & Add-ons at the bottom.
5 Select the plan or service, click Continue.
6 Review the summary and click Agree & submit.


#ROF# (#763#) Turn off international data roaming.
#RON# (#766#) Turn on international data roaming.