What's the connection between being an illegal immigrant and having a valid ID?
In my experience as a traveller, any ID from any country is good enough to get a mobile contract. Some countries might check VISA status too, but any valid temporary VISA is generally enough.
In my experience as a traveller, any ID from any country is good enough to get a mobile contract. Some countries might check VISA status too, but any valid temporary VISA is generally enough.