AT&T locking iphones on installment plans

Yes, that’s exactly how it is supposed to work. You pay off the phone after the credits start and the credits continue until all credits are received provided you keep the line active on a qualifying plan. To be honest, I thought credits stopped when the phone is paid off and I’m skeptical that actually works but @formerlyknownas says credits continue if done that way and she is normally right.

Sure, pay off the phone completely so that you can get it unlocked. It is possible to pay off the phone and still get trade in credits, you just need to wait until credits start and pay off the phone online through your account.

Is it really possible? but if pay off I would lose the credit and my trade-in will have no value. It seems like I can't pay off my phone before 36 months. 

Can i do something like this. Once i start getting credit i pay off my phone and get my phone unlocked and continue  on same plan and credit keeps rolling in for next 3 years. 

We are here to help you with your locking iphones on installment concerns, @tejbirb.

Thank you for the support @sandblaster. To add, yes you are able to pay off your device to get your device unlocked to use when you travel internationally, however once you pay off your device, bill credits will stop.

Bill credits are applied to your account based on the specific terms of the offer.

• One time bill credit: The full bill credit amount will be applied to your bill once the applicable offer requirements have been met. 
• Monthly installment charge bill credit: For certain device offers, bill credits will be applied to your bill in equal amounts towards the device installment charge over the entire agreement term, typically 30 or 36 months. Subject to the specific terms of the offer, the minimum requirements are that:
  • Your services must remain active and in good standing throughout the applicable agreement term. If your wireless service is cancelled, you will owe the remaining installment agreement balance. View your installment plan details
  • The device must remain on its installment agreement for the entire term in order to get all of the bill credits. Typically, if you upgrade the device or pay off the agreement early, the bill credits may cease.
• Other bill credit offers: Bill credits will be applied to your bill as set forth in the applicable offer terms as communicated to you at the time of sale. Individual offers may differ in how the bill credits will be applied.

We hope this information is helpful. Let us know if you have any additional questions as we are always here to hep!

Clarissa, AT&T Community Specialist 

@tejbirb

@sandblaster literally posted everything you need to know and do in the first reply.

1.   Wait until the credits start.

2.   Pay off on your own in your online account by managing your installment.

DO NOT:

Ask AT&T to manage the installment and pay it off for you, not in a store, not on the phone, not with Chat.

DO NOT:

Change your plan to an uneligible plan.

Change phone number.

Suspend service

Cancel service 

Port out your number

Upgrade your line