Carrier Switching ATT to TMO - port without losing service

[iphoneZ]

T Mobile is currently running a free SIM card promo through their website. I'm going to port 4 lines from ATT, but I don't want a service interruption while I'm waiting for their SIM cards to arrive in the mail.

Can I just register new dummy lines then port my numbers once I receive the SIMs? Will this incur any fees?

(I tried asking TMO people but as expected, carrier customer service gets an F.)

 

[iphoneZ]

bumppp

 

[lordofthereef]

You can register new dummy lines and port later without fees. But you can also go into the store and show them the promo and see if they will waive the fees for you. We did four lines a few months ago and they waived it no questions asked. SIM card fees are a ******** nickelt and diming fee that TMO claims to be against anyway.

 

[iphoneZ]

yea i tried that and some mexican dude working in the store tried to hustle and upsell me. lulz. i figured out how to do it online, just order the SIMs and port when I receive them