Effective Feb 17th, 2017:

If you are a new user or existing user on T-Mobile One, ensure you add the One Plus Promo Add on - it's Free and bumps up international roaming speeds to 256Kb/sec

You also get 10GB of full LTE Tethering FOR DOMESTIC/CANADA/MEXICO use - Tethering does not work for other International destinations

Your account should list at my.t-mobile.com, under Plan a Line item for T-Mobile One Plus as follows for EACH line/device:

- T-Mobile One Plus Promo: FREE (256Kb/sec + 10GB Tethering)

- T-Mobile One Plus w/Gogo Full Flight: $5, 256Kb/sec Intl data, 10GB LTE Tether, GoGo Full flight access (more than just the one hour) for Domestic GoGo airline partners, Enhanced Name Caller ID and Voicemail to Text transcription

- T-Mobile One Plus International: $25, 256Kb/sec Intl data, 10GB LTE Tether, GoGo Full flight access, Enhanced Name Caller ID, Voicemail to Text transcription, International calling package (for landline and mobile), unlimited LTE tethering*

* - Unlimited = As much as you want, but when you hit 28GB of total use on that line you will still get full speed LTE when a cell site is NOT congested, if congested you are de-prioritized to lower speeds until no congestion.

You can add the T-Mobile One Plus add ons, including the free promo *ONLY* to accounts where the plan is "T-Mobile One" labeled, cannot be added to Simple Choice or other legacy plans.

Can be added to T-Mobile tablet lines also.

You can make the change online on your own or though 611 customer service