I want to restore my phone to factory settings, which means WhatsApp will be deleted. I use my old number on WhatsApp, and I don't have the SIM card. If I downloaded WhatsApp again and tried to sign in with my old number, can I do that?


  • Old no. 555-1234 - WhatsApp
  • New no. 555-9876 - no WhatsApp

Can I use the old one once again?

  • 1
    Nope I can't anyway, it seems to send an SMS, and register the SIM not the device.
    – RossC
    Feb 10, 2014 at 20:05

1 Answer 1


The way WhatsApp authentication works is that it sends an SMS to the number for verification. This means that you won't be able to re-authenticate to that account without access to the phone number (as you have said in your comment)

A possible workaround is if you root your device, you can back up the WhatsApp data using something like Titanium Backup and then restore it on the fresh install. Depending on how their authentication keys work, you may trick the app into still using your old account.

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