www.t-mobile.com/responsibility/consumer-info/policies/sim-unlock-policy
"Unlock eligibility requirements
We unlock mobile devices that meet the following eligibility criteria free of charge.
Device eligibility is determined as follows:
The device must be sold by T-Mobile.
The device must not be reported as lost, stolen or blocked.
The account associated with the device must be in good standing.
The device must also satisfy all the Postpaid or Prepaid unlocking requirements outlined below.
Unlock eligibility for mobile devices on Postpaid plans
The device must have been active on the T‑Mobile network for at least 40 days on the requesting line.
If the device was financed or leased through T‑Mobile then all payments must be satisfied and the device must be paid in full.
If the device is associated with a canceled account, then the account balance must be zero.
T‑Mobile may request proof of purchase or additional information in its discretion and certain other exceptions may apply.
Unlock eligibility for mobile devices on Prepaid plans
At least 365 days must have passed since the device was activated on the T Mobile network.
If the device was activated less than 365 days ago, then the Prepaid account associated with the device must have had more than $100 in refills during that period for each line active on the account. In addition, more than 14 days must have passed since the device was purchased.
No more than 2 mobile device unlocks have been complete per line of service in the last 12 months.
T‑Mobile may request proof of purchase or additional information in its discretion and certain other exceptions may apply."
