Iphone compatibility with virgin mobile

Yes, you would be able to use it. Take a look at this article (search for Virgin Mobile in your country):

Wireless carrier support and features for iPhone in the United States and Canada - Apple Support

Regards

Giulio

You are not addressing Apple here. This is a user to user support forum and Apple does not participate here. While an unlocked phone should work with Virgin Mobile, you should check with them. Also, to my understanding, they lock phones when you sign with them. I believe it is their way to try and get you to purchase phones from them. Only they can answer if they allow you to bring your own device to their network. Give them a call.

And yes, as ChrisJ4203 suggested, contact them to feel more comfortable :-)

Giulio