Sorry, I meant to say for your current phone. Otherwise you’ll have some sort of road block if the carrier sees your current phone as locked. I had that issue with Sprint years ago.

You can verify by going to Settings->General->About.

Towards the bottom there should be “Carrier Lock” and it should say/list “No SIM Restrictions”.

If it doesn’t, you’ll need to call your provider to have them unlock the phone.

The middle number 555 is used in fake adverts in the US. It’s not used anywhere.