Can my employer see what I'm doing on my Iphone even if the Wi-Fi is off?

I was wondering about that. If I'm on my personal iphone and I'm surfing the web and the Wi-Fi is off. Can they see what I'm doing and if so is it legal?

No, they can't see what you're doing. Your mobile provider can, but your employer can't.

Was the phone bought by your employer? If so its possible for him to look up your internet history. If its yours, and your only using 3g, then its not possible for him to legally track you.