Does your phone need to be on in order for call forwarding to work?

If you forward calls unconditionally (*21), your phone can be turned off and it will still work.

Keep in mind that call forwarding takes your booster minutes twice: once for the incoming call and once more for the forwarding.

Thank you.  I ended up editing my question as you were answering it. Could you review and let me know if there is any change in your answer.

Also, one more question: If I am in the US, will I be able to cancel or add call forwarding through my phone? That is, will I be able to enter the *21 code considering the service limitations in the US?

Ah I missed your additions. You need to set up call forwarding while in Canada. If you wait till you are in the US, I don't think it works. And even if it does, each minute will cost you twice the roaming fee and you'd need a roaming booster.

As for disabling call forwarding while in the US, I believe that is possible but not 100% certain. Paging @BobTheElectrician who knows everything there is to know about prepaid 😊